Semi-Automatic vs Automatic Washing Machines
One does not use a twin tub or even a wringer for "set it and go" quick laundry, but rather for banging though quite allot of wash in very little time, and if done properly with less water than an automatic.
Twin tub washing is nothing more than a very fancy version of wringer washing, with the spinner taking place of the mangle.
The idea is to keep a sucession of wash going from tub to spinner to the lines, with perhaps one or two changes of water.
Unimac (a division of Alliance Laundry Systems), sells a modern commercial twin tub that is a bug hit with car washes, small hotels, restaurants, and other places that generate lots of laundry (mostly small items, but can be up to say a decent sized tablecloth or men's dress shirt), that needs to be done quickly.