If you like layers and masking therein generally that's sort of the image editor end of things as opposed to RAW processor. I realize there's a bunch of overlap, but it generally holds. I'd guess as well that perhaps storing layers in a PIE is a bit of a chore, as opposed to say storing that in PSDs. But maybe it's just sort of artibrary or a marketing thing. LR users have been on about this for a while.
Of course if you go LR subscription you get PS, which can do it.
And several of MacPhun's plugins do layers, like Tonality Pro. It can be handy; you can use presets with each layer, and then blend as desired, which can be faster than readjusting everything manually. And you can just erase say a layer where you applied grain, so that the final image has that masked off the main subject. You can often get to the same place with other tools, but it's more intuitive perhaps for people used to working with them.