You might want to consider Minetest, which comes without an EULA, and has gained quite some traction lately. Having a fully open sourced codebase would be more alongside with Bitcoin's transparency anyway.
I just checked it out. Doesn't seem very popular. As Welsh said, the size of the demographic that both plays Minecraft and is into Bitcoin/cryptocurrency is already notably small. The Minetest x crypto demographic is very likely even smaller. I want to build off an existing, accessible playerbase -- namely, the Minecraft community. After all, you don't need to know jack shit about crypto to join the server. One could join and learn while playing.
This is a massive project, and while it could definitely be possible to do. You might want to try appealing to the more casual Minecraft player, rather than users of Bitcoin. I don't know what the demographic would be for Bitcoiners that also play Minecraft. Instead, you should try promoting it as a way of earning money while playing Minecraft. That would likely appeal to the general public more, and therefore you would generate more players.
That's precisely what I intend to do. I spent a good 25+ hours this last week working on the project and I'm happy to say I'm well into the standalone server that'll run the wallet. The only thing I've touched on the plugin is the code implementation to get it to talk to the wallet/account server.
I'm currently running it on the testnet network and I've gotten deposits and withdrawals to work. I'm planning to finish the standalone server before working on the plugin and in-game mechanics. I'll be creating a simple web interface as well for users to access their accounts and tokens, so in case the Minecraft server is taken offline for maintenance there will still be a way for them to retrieve their funds at any time.
I'm not always at my computer and I'm usually quite busy, so also looking into (minimally) having logging integrated into a Telegram bot. May add notifications through Telegram in the future, things like confirming deposits, miner under attack, plant growth progress, etc.
I've planned out a rough development road map for the Minecraft plugin, researched the libraries I'll use, and out down the base code as well. The current version can be loaded by the latest version Spigot server and will start and connect to the standalone server.
I'll post a proper update or a link to more updates in the OP soon.