What problem does this address?

Using text in cover block is always a question of contras between foreground (= text) and background (= image).
Of course, using the overlay is one option.
But if you want the image visible without any filter in it's whole brilliant colorspace, the overly is a problem.
And if the image has very dark and very bright zones - especially with Fixed background - , you have a problem with text contrast.

What is your proposed solution?

Using CSS text-shadow with X/Y=0, but some pixels for BLUR would work with every background and text color: