I mean, we both know it couldn't, but the company claims it can be done so why don't they do it?

I suppose because generating tokens is slow. It is a limitation of the technology. And when data is coming in slowly, you don't need a super high performance client.

Do you really need an incredibly slow client though?

...I think a vibe-coded Cocoa app could absolutely be more performant than a run-of-the-mill Electron app. It probably wouldn't beat something heavily optimized like VS Code, but most Electron apps aren't like that.