Search costs matter, and GitHub browsing is low friction, but extremely low signal on a very narrow bandwidth.
A lot of the best (technical-wise and ethic-wise) collaborators I've had had and have no public profile, some even not on LinkedIn. You won't find them there.
shrug this is the exact opposite of my experience. All the really great people I've worked with have had at least something there and I've never worked with somebody with a great github profile that wasnt also a great programmer.
Having a decent profile is rare enough that it cant be your whole hiring pipeline but IMHO it's a great reason to let somebody skip an assessment stage or prioritize them for interview.
A lot of the best (technical-wise and ethic-wise) collaborators I've had had and have no public profile, some even not on LinkedIn. You won't find them there.