Sure but with emacs you’d have to do it in MacTerm or another chunk of telnet software, set up a LocalTalk network, etc. whereas this only requires a serial cable and also gives you a native Mac UI to do your editing in
It is also worth noting that there was interest in applications that violated Apple's HIG written for or ported to the classic Mac. I don't know if Emacs was one of them, but vim certainly was. Vim certainly does a better job at violating the HIG than Emacs!
I don’t recall there being a successful Emacs port to classic Mac OS — I would have been very interested in the early to mid 90’s. The Mac editor landscape was actually pretty sparse if you wanted something sophisticated/integrated/customizable. There was Alpha, which was Tcl-based. MPW’s editor wasn’t customizable to the same degree. BBEdit existed, but it was actually quite bare bones at that point; even today it’s still pretty fixed-function.
Correct. Apple had emacs removed from A/UX because it took up too much space. Though some built it on their Macs in the late 1980s, it didn't have full functionality, at least not without headaches.[1] But A/UX came with vi, which worked well.
[1] https://www.tuhs.org/Usenet/comp.unix.aux/1989-September/003...