We have thought a few ways yes. Secondly yes there would be two currencies. A normal currency centralized and a premium currency which would be crypto.
We are welcoming any ideas related to managing crypto and the way it should be in game.
I would look into the system Guild Wars 2 had, and League of Legends has.
Meaning cosmetic only things are sold by premium currency. (Thats your currency sink and guaranteed value)
But I think you would have to act as a exchange to sell those coins to players as well, they could trade it with each other for normal items, and even make a living being good at trading/the game.
You will have a lot of engineering to do there, how to make the transactions safely in game, how to hide the complicated stuff behind a layer of obscurity(all the keys and numbers) so its approachable and still secure
But the thought is kind of exciting.
I would recommend looking into how "Entropia Universe" works, its a game where currency is 1:10 with USD, both in and out. The whole thing is structured like a futuristic-MMO, but its really a casino underneath.
Even doing something like that with crypto would be less fees, more trustworthy