Another use case:

I traveled, and I wanted money. I didn't have a bank account. They sent me Bitcoin, and I exchanged it for local currency, and my problem was solved.

Another:

I don't have a bank account (sleazebags) I wanted to buy a domain, I used btc to get it.

A third:

Let's say I had a bank account, but I couldn't use it to give it to a friend to buy me stuff from his area (some weird laws or tos or something), so I just sent him btc and he got me what I wanted it.

A very important fourth use case:

When I traveled a lot, I didn't need to hold cash, keep it secure somewhere, or transfer money from one bank to another (assuming I could) and lose a lot of money doing that. I just always had access to it and didn't worry about it while traveling.

What's happening around the world fifth use-case:

inflation and hyperinflation.

An even more important sixth use case:

War and fleeing from war