Genuine, non-trolly question: why would I use Atom over Sublime Text? I've used both and by and large they were very effective replacements for each other, but Atom had performance issues with large files so I went back to Sublime. What am I missing out on?
That said, it's missing two very important features from Sublime that I used constantly. First, you can't use it like a scratch pad like Sublime. In Sublime you can open a file, write stuff to it, and it will be persistent. Atom seems to have an option to save your current work, but can't be used this way from my experience. The second is it doesn't have multi-select like Sublime. You can't drag your mouse and have a bunch of different carets. That was TextMate's killer feature imo, and Sublime as well.