I have silent switches in my Atreus, it's quiteter than most membranes I had the misfortune to type on. The feel's better too. And the layout. Mechs have so many great layouts, layouts like the Atreus, ErgoDox, Keyboardio Model01, and so on. Membranes don't have nearly as much variety. Many mechs are also programmable, while very few (if any) membranes are.
That's a couple of reasons for using silent switches over membranes, off the top of my head.