OK, you're right. I used the wrong word. However, I still need to give some “secret code” to make a transaction with my debit card (e.g. the 4 digit code at the back when purchasing online, totally unrelated to my account number). If the whole system is to be trusted, then nobody can spend from my account without that secret code.

It needs to somehow tell your bank that it wants to take funds from there. How can the bank prove that they are trying to spend from the right account?

Of course the bank is a trusted entity, but it's one that needs private keys to confirm who's spending what.

But people don't write 1,000 when they mean 1, and most of the time if they want a thousand they would write 1000 (without comma or dot).

A fiat debit card reader also reads your “private key” (or equivalent for bank accounts). It's essential for it to work.

The problem with that approach is, how do you determine the PIN? Also, desktop and mobile apps would need to include it as well, otherwise we would have two kinds of private keys, and how would that work?
Yet most banks have created apps to make payments with your phone. For me it's more practical to carry a single object to do most stuff.

I understand why a decentralized debit card system would work, but the implementation may be harder than it seems.

The bug was related to incorrectly importing Blockchain.info keys. If you have never imported anything then you have nothing to worry about. Also, it was fixed in the latest release.

How does that affect the scenario described?

The old one will import correctly, but will not contain the new private keys (obviously). Only then will you lose your coins, but only if you are not careful.

OK, I will consider it

Does it support SPV mode? I was thinking on a Windows Phone app, and I don't think it could (or should) run a full node.

As far as I know, “Available to spend” only appears when the amount is less than the total. You should be fine spending it.

Older people also tell me that smartphones are a bad thing and that I should stay away from them.

I want to run a full node, but I don't have any spare computer to leave it running 24/7. I'm planning to buy hosting. Is that a good idea? What specs should the hosting have?

Mega also works on Firefox. There's an extension, but it's optional. Maybe we could download the extension and see its source to find if encryption is done there...

No, but the different logo may be noticed, and if they click it, they will see this news.

Where does it say what?
That it's FUD? People don't usually say their own post is FUD.
That it was an imported key? Here.

That article is FUD. It's the same user that complained with everyone about losing their imported keys.

Th bug was actually pretty hard to hit, and it has already been fixed in the latest version.

You mean, like the Philosopher's Stone in HP1?

His nose will not grow. What Pinocchio states is a prediction, which can be neither true nor false at the time it is stated.