They're doing it before a significant user base grows that precipitates a github-for-3D startup. Building this feature also fosters growth of open source 3D modeling and printing, which is a net positive thing.
It is a net positive, I just wish they would focus more on their core users. Their basic code diff tool could use a lot of love to make it on par with the diffs generated from other tools.
I wonder if it really will though. As mentioned elsewhere in this thread, STL is an output format (think PostScript) that I would be a little bit surprised to see checked in to a repository. Maybe diffs for 3D source formats will come in the future?
