Time and expertise to manage that server. It's cool that there's a Golang server out there that's a one binary solution to this among other offerings but some expertise and time is still required.

I would rather a student learn how to use git and the communities and tools around it first if both of these were options.

Are you oblivious to the amount of open source work that happens on Github?

Nothing I said implied anything of the sort.

You implied that was all that was offered by these sites by asking a leading question instead of an open one.