Many of the things you mention are absolutely in nano :) Like highlighting, jumping to a line, importing.. I don't have the time to do a point by point comparison but trying nano for 5 minutes doesn't equate knowing it, just like with vim.
I'm not big into coding anymore and nano is handy for my muscle memory, coming from DOS :) It's good enough for my purposes. Sure vim is more powerful but it's not as accessible to the casual user. It's a good tool for its job just like vim is. They're just different jobs.
Absolutely. I use loads of those features including regexp in nano all the time and it works fantastically well. For me it's the fact that it's small (so available on nearly every platform) and the command interface is so quick. It's light, fast, and snappy to drive - no context "shifts" to get to commands, and I can do "power user stuff" with just a simple key shortcut _which is written on the screen so you can see it_ most of the time. It's easy, and that's worth more than a thousand vims. See also the success of Visual Studio Code.
I'm not big into coding anymore and nano is handy for my muscle memory, coming from DOS :) It's good enough for my purposes. Sure vim is more powerful but it's not as accessible to the casual user. It's a good tool for its job just like vim is. They're just different jobs.