Bit late to the party, but I wish I had learned properly what “rebasing” is exactly a bit earlier down the line… It took me so long to figure it out while it’s useful to me now.
What I loved (and actually still do very much) about GitHub is that it provides that visual assistance in the form of a handy GUI when it comes to my Git repository - it’s something else than the command line over and over. I know there are other tools out there that run locally, but GitHub proves to be sufficient for my needs.
Oh, and also that I can easily check a bit of code out from my phone or (more often) iPad is pretty neat!