As someone who does both, I have to say that the only reason I am writing MCP stuff is that all the user-side tools seem to support it.
And the moment we, as an industry, settle on something sane, I will rip out the whole thing and adopt that, because MCP brings _nothing_ to the table that I could not do with a "proper" API using completely standard tooling.
Then again, I have run the whole gamut since the EDI and Enterprise JavaBeans era, XML-RPC, etc. - the works. Our industry loves creating new API surfaces and semantics without a) properly designing them from the start and b) aiming for a level of re-use that is neither pathological nor wasteful of developer time, so I'm used to people from "new fields of computing" ignoring established wisdom and rolling their own API "conventions".
But, again, the instant something less contrived and more integratable comes along, I will gleefully rm -rf the entire thing and move over, and many people in the enterprise field feel exactly the same - we've spent decades builting API management solutions with proper controls, and MCP bodges all of that up.