Grumpy looks to me like it was created as a bridge to port everything to Go. If you look at it from that perspective and know that Google has a lot of existing

Grumpy looks to me like it was created as a bridge to port everything to Go. If you look at it from that perspective and know that Google has a lot of existing python 2 code base, it makes a lot of sense. If they wanted to stick with python, instead of grumpy, they would instead provide a way to write python modules in go.