Being able to offer a helpful API to the world and just getting paid whenever someone uses it would be really nice.
At the moment you have to process the payment "yourself" (even if you use a third party for that), issue an API key, etc.
I don't think you can make money on them, they are too simple to clone, but you can make money charging for the API. If you have a per usage license making an MCP is a very obvious choice - if you charge per seat it is mostly a question of how how sticky you are versus the competition.
With some kind of MCP tip jar, they could extract the data they need and pay $0.02 for the service.
It would remove a lot of friction in the system, and could generate revenues for content & data creators.