Git and HTML both deal with the (let's face it) complicated data structure we all know as trees.

The difference: You can fuck up an HTML tree and most browsers can still display your page[1], you can still get your message across. You fuck up a git history tree and you can somehow summon Cthulhu.

Not to mention, even if you can manage to stay away from branch confusion, just dealing with diffs is already a huge barrier for newbies.

[1] See "Where HTML 'beats' C" - Computerphile https://www.youtube.com/watch?v=-csXdj4WVwA