Yes, it's great for businesses, you can search for the cheapest labor, and helps you avoid paying someone much more than they previously earned.
And private individuals as well, as you can see what your colleagues earn without having to ask anyone, and can even see what your boss earns, or what the competitor to your current workplace earns! I have to say salary negotiations are a lot more straightforward (and fun) in Sweden as an employee than other places I've worked.
Overall the benefits for employees seems way broader than the benefits for the companies.
That's more of an American thing, wages in places like Denmark are much more set by the job classification and maybe seniority, not individually based on one's background and what one previously earned.