Edit: gigabytes of ram.
In the Emacs case, Stallman just made that explicit, implementing Lisp from the start.
is an old meme.
> I am not an emacs or vim user, but doesn't emacs support vim style editing(key bindings) or it supports just a subset of vim?
it supports quite a bit via Evil.
Unless you are a Vim connoisseur you will not be disappointed.
Also Emacs cannot be 100% Vim compatible because their control schemes are so different, example: The cursed Esc key which doesn't work properly even in Spacemacs. There's a huge difference between Emacs with some Vim commands and Vim with Emacs functionality.
So, I'm staying with Vim and if others prefer Emacs that's fine too.