You just have absolutely no idea what you're talking about. You can literally buy food from Burger King with crypto. It serves the EXACT same purpose.
It's not an assertion, it's just pure fact. You even agree with me. LOL.
What part, specifically, do you disagree?
Do you think you can't exchange it for dollars?
Do you think you can't buy things with it?
You just have now said that legitimate businesses accept it. I get that for whatever reason you don't want them to (which is just a bizarre take), but you are saying that legit business take bitcoin. So that is the purpose. Just like every other form of currency. It's to exchange for goods, services, and/or other currencies.
In your bizarre post, you've now talked about how they check all three of those boxes. You don't even disagree with me, but the idea of currency confuses you so much that you haven't realized it.