The biggest threat to BTC is the 51% attack, as huge corporations and very rich people already have tons of high tech computers mining Bitcoin everyday, the threat of a 51% attack is not that far in the future. That is the ultimate fail for Bitcoin, as new better alt coins will take up the lead.
Bitcoin serves no real purpose in Real Life, 10 minute block time is extremely impractical, that's why many Real life business don't accept bitcoin for small purchases.
Bitcoin's main job is a means of investment, with only 245k people worldwide having at least 1 bitcoin in their wallet.
Bitcoin is very vulnerable, especially to a 51% attack, compared with other Alt coins
Bitcoin has had a 6 year start, or rather 2 and a half year start compared to other alt coins such as Litecoin etc etc
Bitcoin's price can fluctuate unknowingly/uncontrollable such as when it dropped from over 600 usd to under 300 usd in a matter of hours on Mt.Gox. That's also a reason real world business Do Not Accept Bitcoin as a means of payment(They don't want you to spend 1 bitcoin buying a laptop worth 700 usd for example, and the price of bitcoins crashes the next day to under 200 usd, that'll mean they lost over 500 usd)
OVERALL DIAGNOSIS: Bitcoin is doomed to fail...soon (anyone saying otherwise is either 1) Investing their money in Bitcoin, an admirable short term way to make money with Bitcoins fluctuating prices, from 200usd to over 1k usd in a few hours sometimes such as in November.. or 2) Delusional.)
Open your eyes, new better Alt coins are being thought of are worked on everyday, they are the future of virtual currency, Not Bitcoin.
When speculators enter the alt market for their trades, they convert their fiat into... Doge...Nxt...MaxCoin...Litecoin...Vertcoin...HBN? No, Bitcoin. Bitcoin is the gateway to the rest.
Oh, and if Bitcoin price falls, that's an easier entry for people with fiat! If my same 1000€ or Goldman Sachs $1B buys more BTC, that means more alts, more flexibility and volatility, higher chances of profit! "My", so to speak, because I don't speculate with fiat. If Bitcoin fails, other coins can't stand on their feet alone.
As said before, nobody needs n-confirmations for a cup of coffee. I got some PC games and didn't need confirms. Small items do not need them!.
Regarding the 51% attack, it's not needed. All it takes is being banned/criminalized by law, a SWAT team to force who's-who in Bitcoin to make destructive changes at gunpoint, or hacking whatever distributes Bitcoin software. The day it happens, you will be worried with much more than cryptos either way.
Edit: nowhere I'm suggesting anyone to hold all your crypto-money in BTC, that's just my opinion. Be careful
