In my (admittedly limited) experience, mandating salary transparency tends to increase the salaries of low performers and reduce the salaries of high performers. It usually eliminates the potential for negotiating raises and poses difficult questions about paying some employees more than others in the same band.
Case in point: according to Buffer's salary calculator[1], a "master" (their highest rank) backend developer living in San Francisco and optimizing for salary over equity would earn about $155,000/year. I can't think of any definition of "master" developer that could be competitive for. Friends of mine at AmaGooBookSoft and even other startups have earned nearly double that for being merely "senior" (L5).