No: most online games don't maintain a marketplace where users can trade their assets for cash, running auctions or whatever similar to eBay. That is the issue here: people want to be able to sell their cards to other players, and now you need to build a mechanism that supports that correctly without becoming riled in the customer support issues.

Also, BTW: part of what makes the physical cards valuable in the long term is that even if the company that sold them goes out of business, the cards don't disappear and they still work to play the game... your dismissive attempt to build this sort of thing using centralized tech is thereby pretty ridiculous on the face of it even if you didn't try to tackle the money issues yourself.

What you want is a game that has no backend and preferably is coded using forwards-compatible technologies like HTML/JavaScript that can use these APIs to access their state for the long term... and again, that's Ethereum.

(Note: I ran a market for apps for over a decade and before that I was a game developer for almost half a decade; I thereby know what things are and aren't hard.)