[iKnowKungFoo]

It's analytics. Google search brings up

https://www.cockroachlabs.com/blog/what-can-we-learn-from-ou...

"Years ago I dedicated a Flex Friday (our version of 20% time) to stargazers, a tool to query the CockroachDB repository for information about its GitHub stars and analyze the results. At the time of writing, we had 6,000+ stars (which felt like a lot), and the data in this blog will be based on that original set of 6,000 stargazers."

Which links to

https://github.com/spencerkimball/stargazers

"GitHub allows visitors to star a repo to bookmark it for later perusal. Stars represent a casual interest in a repo, and when enough of them accumulate, it's natural to wonder what's driving interest. Stargazers attempts to get a handle on who these users are by finding out what else they've starred, which other repositories they've contributed to, and who's following them on GitHub."

[forgotpwd16]

This doesn't answer OP's question. OP asks why projects link to the page showing who starred them, not what some tool named stargazers does or/and what data can be gathered from people that starred a project.

edit: Thinking about it, probably does. Basically someone will check the stargazers page to find what people that have starred a particular project are up to or what else they may have found. This may seen as a waste of time on projects with numerous stars but becomes really useful in small niche projects with low number of stars.