I'm wondering—if you prefer VSCode, why even comment a post about Atom? I doubt your care that much..?
Atom is built on Electron. That means that it includes a whole version of Chromium (OMG!), and it isn't even optimized, so its size is 5 times that of VSCode.
Is that really a problem? Are you trying to tell me that as a developer you don't have 400MB to spare on your hard disk for one of—if not the most—important tool to work your job, and the size is really a reason to pick one editor over another?
Atom is about 100 times slower than Sublime Text, and like you pointed out 5 times bigger than the insuperable VSCode.
Now, I use Atom as my main editor, because I find it simpler than others for certain things, and it saves be a lot of time because GitHub integration is done very well. Also, I like the name (can't say the same thing about VSCode).
Some people like Atom because they're more productive, and don't care about its size, super-crappy speed, and whatever else you think Atom is worse than VSCode at.
Can we put this thing to rest..?