You can prove you actually own how much you want to prove you actually own, without leaking any other information on your identity or current wealth. You can sign documents. You can mount complex escrow processes with it. You can send it worldwide to anybody without even knowing where they live (phone numbers fail), or what their bank is (IBANs fail) or what their email is (gift cards fail) or whether they are allowed by someone else to receive money (paypal fails). You can pool it with friends and set up conditions for safe withdrawal reliant on multiple people agreeing at the same time. And you can receive money from anyone, anywhere around the world, without anyone else's permission.