Designers have portfolios. Would you do them away as "advertisements" as well? They are much more than that, e.g. they show the skills of the designer.
The key difference is that designers are free to show the work they've done in their current jobs or internships. Programmers usually aren't at liberty to do the same.
If I read correctly the idea is not to do away with repos but rather not using that as the single signal.
Just like you shouldn't exclude any companies just because they don't advertise.