This is due to Git's tight integration with regards to branches and namespaced branches though isn't it? Hg push isn't aware of bookmarks as far as I know, so Git has more to explain compared to Hg, where lightweight branches are a plugin. Or am I wrong on this?
It is still a plugin, it's just bundled/installed by default. I've worked with Mercurial for the better part of a year, I'm not clueless about it.
But yeah, since branches/bookmarks are an integral part of how you work with Git, you also have more options regarding branches/bookmarks in several git commands. Git allows you to push a local branch to a remote branch of a different name. This is helpfull when you're pushing to different remotes, and the some of the local branches should map to master on different remotes. But this of course requires more information to stand in git pull's documentation. There are, of course, other features as well.
Just because git push has some 'advanced' featues, doesn't make the actual push command difficult to understand though. Most of the time you just use 'git push', same as Mercurial, git just allows you to do more with git push than what Mercurial allows you to.
