Yeah, if you want to use less resources Gogs is a great option. Did you know out team member Kim works on Gogs fulltime? https://about.gitlab.com/gogs/
Joking aside. Most likely to get a foot in the door on competition and on git related features written in Go, which might supplement or replace parts of the infrastructure within Gitlab. They already use Go for the CI runner part and as a smart, Gitlab aware proxy.