I see some users are suggesting that you should create some in-game currency that can be converted to Crypto, but for me it kind of defeats the purpose. I want to see a server where you can use Bitcoin (BTC) as the economy and not some kind of fantasy token. (We see lots of games where in-game currencies are created and in some of these games, people pre-mine them to enrich themselves)
The issue is, your probably restricted by Mojang's EULA. They probably won't authorize the ability for a real life currency to be earned, and sold via in game. I haven't checked the EULA in a long time, but most games have similar policies in place which restrict the purchasing, and selling of in game items, and I'm sure a lot of them have extended that to cryptocurrencies ever since they have emerged.
By creating a in game currency, it'll probably be easier to work with the EULA. Also, it does save a butt load of work trying to implement Bitcoin into the server. The virtual currency could operate the exact same, and is probably a more secure implementation, since you aren't storing Bitcoin on the server. Instead, users would earn the virtual currency, and then request a withdrawal at x time.
Its just like how your bank account works. The money that you see on your screen isn't actually cash/good or whatever. Its just a number, which is processed later on down the line, rather than immediately as you push withdraw or send.