I could probably list about 100 reasons, since as a founder, user, and (ahem) PRO member of CodePen myself, I’m motivated to do so. But let me just list a few here. Some of these are my favorites, some are what PRO members have told us are their favorite, and some are lesser-known but very awesome.
1) No-hassle Debug View
Debug View is a way to look at your the Pen you’ve built with zero CodePen UI around it and …
4 Reasons to Go PRO on CodePen is a post from CSS-Tricks