Of course MCP has its use case like if you want auth, or session based actions.
NO IT CANT!!! why dont you understand that not all agents have access to a terminal!
Recent example: The AWS CLI has a convenient "s3 sync" command that does a one-way directory sync, only downloadiong new files if existing files with matching sizes and timestamps don't exist, but the closest thing the .NET SDK has unconditionally overwrites destination files.
Another example: one of the nicest things about C# is how the compiler exposes itself as extensive library functionality, so, not only can I compile and run code at runtime, I can generate this code from programmatically created ASTs instead of text, parse expressions into ASTs, etc.
These are things devs often take for granted as being part of ‘how chat agents operate’ but they are specific to how claude code/opencode/pi/codex operate.
Giving agents a Unix computer account they can play with is definitely a powerful tool that makes them capable of doing a lot more (see: meta muse, OpenAI dots), in much the same way that giving a human a computer they are trained to use makes them way more capable… but it’s surely not the only way we can run these things.
They pay tons of money for hardware, only to use it the same way I was using those DG/UX terminals at the university.
Naturally there are no coders in other operating systems as well.