Yeah I am thinking this is a feature that is not really useful but a real gimmick - I use mine for a lot of stuff, but I use it properly, always with water running- letting it go after its "done" putting dish-soap in it and letting it get all super bubble - and orange/lemon peel every now and then is nice.
The disposal I first had was a badger from the first owner, who knows how old the thing was and I had it a good 5/6 years and it didn't stink... no little purple light is going to keep something truly rotten from smelling in there..
The insinkerators seem to be the good standard still for best of class, they have stainless bottom ones now... the fully stainless industrial ones are 1500$+ so...yeah not them.