mac pbcopy/paste into emacs does strange and horrible things. Mouse and scroll-wheel integration roughly doesn't work at all. The list is long.
I also use terminal tools a lot (data engineering), so the terminal itself (and hence tmux) is an important part of my toolset. Meaning, I can't abandon the terminal. Nor do I want to -- as others have said, I have RSI issues with touchpads and mouse-clicking. Spectacle on Mac (or any actual tiling window manager on linux desktops) helps with that, but if I never had to touch a mouse/trackball again in my life, that would be awesome.
As others have said, I mostly want to use an integrated editor and get on with my job, rather than go down a half-century old rabbit hole of reading SICP just to tweak some editor defaults. Again, don't misunderstand me: learning LISP changed my life, man. But that's not the same as "can I enable rainbow delimiters for protobuf" (As an aside, Little Schemer is a much gentler intro to LISP, and also awesome.)
And since I know we're a community of people who get distracted by the next shiny problem to solve: please don't focus on trying to fix the list of issues I'm describing. That's not the point (and I have no spare weekends).