They're fat/inefficient because of the electron base, so they use more RAM and resources to run than a native app would.

Obsidian, for example, takes over 2x as much RAM on my computer as Emacs does, which is crazy.

Add to this the fact that they all have to work with basically the lowest common denominator of interfaces, which means they're consistent across platforms but also completely eschew anything native on any of those platforms. In the Mac world, this is especially egregious because we as a tribe tend to actually LIKE the way the Mac does things.

There's a phrase popularized by Brent Simmons about this: Mac-assed Mac apps. See

https://daringfireball.net/linked/2020/03/20/mac-assed-mac-a...