I just view it as a relative minor convenience, but it's not some game-changer IMO.

The tool use / function calling thing far predates Anthropic releasing the MCP specification and it really wasn't that onerous to do before either. You could provide a json schema spec and tell the model to generate compliant json to pass to the API in question. MCP doesn't inherently solve any of the problems that come up in that sort of workflow, but it does provide an idiomatic approach for it (so there's a non-zero value there, but not much).