No, there it works as a tradable commodity.

Different. Similar, but different. It's an important difference too.

I can't imagine the majority of users are criminals.

I've recently tried it out as a means of receiving payment for completely legitimate work. The client was in a different country. The contract was signed in USD. Client sends half at then exchange rate, which arrived very fast. After accepting the delivered work the client sends the other half, which was less BTC because the price went up by that point. But it didn't matter because the first half I was holding appreciated so it's all the same. Turned out one of my vendors likes Bitcoin so I used some of it to settle an outstanding bill with him, then sold the rest at an exchange. Opening that account for the company was a pain in the ass, though less painful that opening a typical brokerage account. I had to pay a fee to the exchange to sell and another fee for them to wire the funds to my bank. It was faster and cost less than a credit card. It was more expensive than a check, but way way way faster. It was cheaper than SWIFT overall, but a few dollars more expensive to me because I bore the costs of selling while the client only bore the tiny costs of the Bitcoin transaction fees. If the contract was for a much larger amount then SWIFT would have been better. For accounting purposes I'm just treating BTC as a foreign currency. I would accept it again, it's great to actually receive payment that fast.

I'm using Bitcoin to get paid, withdraw to ATM/Bank accounts, hold wealth (yes in Bitcoin) and actively day trade. I also use it purchase stuff online on sites that accept bitcoin.

No, I don't deal with drugs/criminal users.

"It gets traded sometimes" != "It's a currency"

So, the current banking system?

The way I recall it, they didn’t void past transactions; they added “irregular state changes” that would “return” the “stolen” funds to their “legitimate“ owners. Nor were they forced to fork; it was a voluntary decision of a group of people with enough social power over the platform.

Now this is more a matter of dispute, but I wouldn’t say the hacker stole the funds. They simply followed the DAO contract (not the “smart-contract”, mind you, but the one put forward by the Slock.it team on their page), according to which everything that went on the blockchain according to the DAO code was legitimate.

Nobody forced anything. A bunch of people agreed to use new rules with old data, which is why the new chain is in common use. Democracy in action. The same could happen to literally any cryptocurrency you could think up, unless you can come up with a way of invalidating past state to a point where nobody can use it with a new set of rules - which is impossible unless you can somehow cryptographically encode the rules into the chain to a point where you can't access the data without adhering to the rules. (I think a zkSNARK could help with this if it's something that people actually desire.)