I work in an industry (Tech) where stock-based compensation for senior folks like me is > 50% of my compensation, and in many cases, that's where the difference in pay arises. Having just the cash compensation made available isn't terribly helpful. For example, my current job has a 5% higher salary than a previous job, but my total income is about 50-60% lower (I'm also much, much happier, FWIW)

All that said, I think the folks that this really is designed to help will substantially benefit from having greatly increased transparency.