Do Book Editing Services Really Improve Quality?

Has anyone here used book editing services​ and noticed a significant difference in their manuscript? There are so many types—developmental, line editing, proofreading—but how do you know which one you actually need? And are professional editors worth the cost, or can beta readers cover most issues? I’m curious to hear real experiences from authors about what worked, what didn’t, and whether professional editing truly helped elevate the final version of their book.