That is a question that I come across quite often. For example,
I understand all the ideological reasons for why someone might want to choose Bitcoin. Most of them are fairly crazy, but at least they're there. What I don't get are the practical benefits, why an average person would actually choose to use them. If you aren't worried about the government or the banks or planning to get rich quickly 2140, then what can Bitcoin actually do for you? That's the part that nobody has really managed to explain so far in any of the threads, at least as far as I can remember.
To be fair, we understand the currency, it's inner workings, and thus its potential quite well, but while we profess how great it is, with $'s and stars in our eyes, we likely forget that the people we are talking to don't know or understand everything that we do. So, I think we should come up with some examples that answer the question of "why would an average person care" (or re-paste them from older necro threads). Here are some of mine:
1) It lets you send money overseas cheaper than using a bank wire (FIAT > BTC > BTC > FIAT has way better fees and exchange rates than bank wire, Western Union, etc).
2) It lets anyone open a virtual bank account without needing access to a physical bank. For example, some banks charge fees and require minimum balances for accounts, which may be prohibitively expensive. Some areas around the world don't even have banks other than in far away big cities. And in some cases, it's easier to just create a new Bitcoin wallet to store money in, than it is to drive down to a bank, fill out forms, come up with profs of ID, wait days for them to be verified, and another week for your account to actually be ready to use (especially if you're looking for a small business account).
3) It lets you accept payments online easily and way cheaper than with VISA, PayPal, or other such services. Heck, you can even just get a bitcoin address from MtGox or any other exchange, set up your account to instantly exchange any received BTC for local currency, and you're done.
4) It lets you accept payments over e-mail or any other service that can transmit text (even photos, as seen on girlsgonebitcoin). Some sellers may not have the means to build a website, but can still send out an invoice, asking to send payments to a specific address. (i.e. someone living in a poor country who only has access to an internet cafe, or someone who just doesn't have web skills).
5) It lets you accept tips or donations using any website. You can upload videos to YouTube, photos to Flickr, posts to a blog, music to Soundcloud, art to Deviantart, or comic strips to GoComics, and to accept donations all you need is to include a string of text in the description. No need to set up any money-accepting plugins, set up any bank or financial accounts, or rely on features provided by the service being used.
5) It lets you send money to places where PalPal or other money transmitting services are blocked, for example Russia or India, and is much cheaper for sending money to family in other countries. Even if that country they can't send money to is US, as in the example of the parents in Iran sending $2,000 to their college student son living here.
6) It lets you send huge sums of money overseas quickly and cheaply. If you were in US and you needed to pay $1,000,000 for a shipment from China, using normal methods of wiring money would take two or more weeks, and will cost more than $25,000 for the transaction. With Bitcoin, it takes a few hours, and costs $12,000 or less.
7) It lets you send micropayments better than anything else out there. It's easy and practically free to send $0.01 to anyone else using BTC, but would cost about $0.25 for just the fee to use the USD/EUR system. Any micropayment system that uses USD/EUR would have to sit on top of a larger system that stores all the money in a single large account, and all micropayments would have to be done as accounting entries within that account, instead of money actually moving around (i.e. you have to fund the system with a large payment, do your micropayment transactions, and withdraw when your fund is big enough again). This means micropayments using USD/EUR are restricted to only within specific services (i.e. your pre-paid micropayments fund that you use to pay for news articles can only be used within that news website)
8) It lets you create programs and services with their own bank accounts (the software stores value, as opposed to value always being linked to a real world person and a real world outside-the-service bank account). The Reddit tipbot is an excellent example of this, and would be impossible with USD/EUR, since to build it using FIAT, someone would have to open a real world bank account under their name (with all the forms, proofs of ID, etc), set it up to accept money transfers from others using PayPal, VISA, or something else, which will charge fees, have nasty exchange rates, have to keep to strict AML regulations, and be restricted to certain specific countries. Plus it would have all the micropayment issues mentioned above. With Bitcoin, all the "banking" is done with software, requiring no permissions, and no single programmer's name has to be linked with any bank accounts.
9) It lets you instantly fund USD/EUR based accounts around the world. The small LLC I started up keeps a BTC cash account for minor business expenses, and my business partners around the world will have Bitcoin funded VISA debit cards (as soon as Bitinstant releases them). That way, all the money is stored safely in the business vault, and if they need to pay for any business expenses, no matter where they are on the planet, or what their home currency is, I can fund their cards from home within 10 minutes. That's impossible with ACH, wires, or whatever else is out there.
10) It lets you link a payment account to a contract using address signing. For example, Person A agrees to buy Person B's debt. They write up an agreement contract, and instead of signing it with PGP keys, they sign it with A's and B's bitcoin addresses. Then money is sent from Address A to Address B, and any repayments are sent from Address B to Address A. That way, Person B can't claim that they never received the money, and Person A can't claim that they are still owed more than they really are, since all transactions are publicly verifiable on the block chain using the very addresses that were used to sign the contract. There is no need for any legal disputes of who owes what, since the blockchain keeps both parties honest (I actually did this already).
If you can think of anything else, please add it to the list.