The USD figure is more akin to valuation of a company than that amount of USD in hard currency. Probably not inclusive of expenses and risks associated with converting it into cash.

How that value is earned and calculated are interesting questions.

Nobody got scammed. It's pretty much like an IPO. The project distributed tokens, not dollars. Coinbase and a few other exchanges listed them and trading started with the tokens fetching a certain price. I sold some on Coinbase, got money - that's it. The token is a "governance token" and I, personally, don't see much value in it but I do not follow this too closely. In theory the token gives the holder a future say in the direction of the projects and maybe a cut of the profits.