Because Claude has that as a built-in tool. Try Claude on web and see how useless AI is without tools.

And don't even get me start with giving AI your entire system in one tool, it's good for toying around only.

Why would I use Claude on web to do that? Why would I use the wrong tool for the job?

I am not saying you should. I am pointing out AI without tools (which I believe is what you think of when you refer to MCP) is useless.