There was some previous discussion about it here: https://news.ycombinator.com/item?id=8562483
Unless you make it a requirement to do the entire thing on that platform...
This tool even blows that out of the water.
I wonder how long before some groups recommend/require something like this to provide evidence of originality.
Also, this is just one signal and would be powerful as the preliminary one. There would probably be a few false positives, but nearly no false negatives. It's not like kids are going to be expelled for copy/pasting documents, but it certainly warrants more suspicion.
I think there are great possibilities for building on this idea...