These corner units have built-in electronics so that every single function can be fully electronically controlled. It's not just drive-by-wire, it's steer-by-wire, brake-by-wire, everything-by-wire. So you can put a steering wheel and pedals in if you want, but it's just as happy to take instructions from an autonomous drive system, even a remote control. There's no difference as far as the chassis is concerned.
What could it be used for? Well, just about any kind of electric 4-wheeler. The big, flat battery pack offers a genuine "skateboard chassis" on top of which your vehicle design options are just about unlimited. There's no other chassis so flat, or that offers so much room for whatever kind of body you want to stick on top, be it a car, van, truck, bus, automated delivery vehicle or off-roader.
It's a remarkably flexible and practical system, and some major automakers are buying in, seeing the wisdom behind working with a chassis that only needs to be crash-tested and approved once to be relevant for a broad range of vehicles.
Toyota has partnered with REE on its 'Flatformer' range of electric Hino vehicles, which will include everything from passenger shuttles and delivery vans to garbage trucks, food trucks and mobile medical services.
More recently, Indian automaking colossus Mahindra signed an MoA with REE to develop and build an initial run of up to a quarter of a million commercial EVs.