Rust + EDITOR.COM is kind of like remaking/remastering an old video game.
I guess they thought that inheriting 25 years of C code was more trouble than designing a new editor from scratch. But you'd have to ask the devs why they decided to go down that route
Yes, but you have to put `set mouse` into your nanorc.
This is not a rewrite. Maybe it’s slightly inspired by the old thing, especially with having GUI-style clickable menus (something not seen often in terminal editors), but it’s much more modern.
CUA-style menubars aren't that uncommon in textmode editors. Midnight Commander's editor has traditional menubars with much more extensive functionality, as does jedsoft.org's Jed editor. Both of these also support mouse input on the TTY console via GPM, not just within a graphical terminal.