A teacher that needs to know the kids that are struggling the most with a recent exam doesn't want to ask the AI 10 different ways, deal with hallucinations and frustrations, send tech support a ticket only to receive a response that the MCP doesn't support that yet - isn't going to be impressed.
They just want to see a menu of available reports, and if the one they want isn't there, move on to a different way of doing what they need.
The user needs to able to discover the capabilities and limitations of the system they are using.
For most practical examples I can think of, this approach would complicate that, if not make it nearly impossible.