The "Gist" comparison isn't really apples-to-apples. GitHub Gists are actually git repositories themselves, and can be cloned/pulled/merged/pushed/etc. Gitlab Snippets are assets connected to the project. I remember a feature request a while back to make Gitlab Snippets more like GitHub Gists, but can't seem to find it on the actual Gitlab project's issues section now.
Huge fan of Gitlab, though. We're about to migrate from BitBucket Server née Stash to Gitlab CE.
Maybe that says more about the Gist UI than anything else. I still think there's a chance for a Git-backed OneNote clone to really take off - if you hid Git away for normal users it would be really powerful.
I think some concept of scratch/temporary repositories might be better than a Gist-style thing, but Gist with a better UI might work too.
Huge fan of Gitlab, though. We're about to migrate from BitBucket Server née Stash to Gitlab CE.