I beg your pardon, but since Linux is increasingly used nowadays in quite resource constrained embedded devices, MB definitely does matter. (No, I don't claim that the individual 10 MB is very much on most devices that are actually capable of running linux. But once you go down that road and start having something else bloated than just the text editor, you are a few hundred MBs poorer in no time, and that is a lot.)
How are those relevant in our context?
Most of those "constrained embedded devices" (from smartphones to IoT and set top boxes) don't run terminals and editors anyway. And those that do belong to a niche, and those people can install whatever they want, be it nano, micro or whatever fits.
If you're concerned about the programmers of those "constrained embedded devices", that might want to ssh and edit something on them, then those programmers don't use nano anyway, so this doesn't concern them either.
https://blog.filippo.io/shrink-your-go-binaries-with-this-on...
Because MB don't matter. It's about the experience it offers (e.g. as a better nano for early users) or doesn't offer.
Nobody cares if Emacs is only 3MB more -- it's not an argument for "just use Emacs then".