For one thing it's extremely mouse-driven, which is already disqualifying in my book but to each their own.
The whole "anything can be a tag and you can execute it by clicking the middle mouse button" can seem novel and exciting if you've never used Emacs, which did the whole "everything is configurable and scriptable" a long time ago and IMO better.
Then the lack of syntax highlighting is pure elitism in my book. I tried to give that a chance but when you listen to the arguments of its proponents it often boils down to "colors are childish" and "books are black on white and we read those just fine" which makes complete sense unless you think about it for two seconds.
I genuinely don't get it. When I first read a Vi(m) tutorial it seemed esoteric, complicated and weird, but I understood why some people found it more efficient that way. Watching somebody explain acme reminds me of TempleOS, filled with weird idiosyncrasies of dubious usefulness while lacking super basic features.