Is it really a social network though?

I use stars as bookmarks. I never even notice or pay attention to profile achievements. I am actually rarely even on a profile page. I am almost always in a repository either looking at code, issues, discussions, or reviewing.

Popular and good are only loosely related.

Star counts on a repo are both essential for devs who need to assess a range of libraries/products for possible use in their own product (as indirect indicators of support, community, etc), and yet also toxic for anyone trying to build a new library/product in an established niche (everyone ignores repos with low star counts).

Clearly if I was serious about marketing/promoting my library then asking people to star the repo would be high on the list of asks. Sadly I am not that person.

On the other hand, having starring a repo made into a game will skew the stars' usability in gauging a project's popularity or quality. Maybe the "most starred repo for X" is just made by someone who's really into collecting badges or marketing.