We *Had* It
Our previous home had a Valet Central Vacuum System, from 1987.
Prior to our purchase of the home, the home was a rental, and some previous tenants (stupidly) used the system to vacuum dog-leavings from around the house/yard. Seriously.
So the system needed some TLC when we moved in. She worked as good as anything until 2007 or so, when we had a new motor fitted to the system. The newer motor was clearly less powerful, and sounded like it was straining most of the time. Nonetheless, it still worked a treat.
We'd be happy to have another. No fuss with exchanging the electric cord as you move through the house, dragging around a heavy canister, trying to work it over bumpy tiles and electric cords. The largest benefit for us was with the Slate tiles in our previous home, it made it difficult to move a vacuum around the place. So the central unit was convenient (and the house was 5 bedrooms, 2.5 baths, laundry, study, kitchen, dining, games formal dining).