Motion activated things on public spaces are there so everybody does not have to place their dirty hands on the same surfaces. It's a public health issue that does not make sense at all on private or even semi-private spaces.
While hygiene may be a auxiliary benefit if it were really about hygiene they'd give you more than a trickle of cold water.
A normal amount of warm water encourages people to wash their hands correctly. I have to sit through around five on-off cycles to get a good hand washing.
Makes sense, although I have to ask: are they a net saving in waste water and processing versus resources required to manufacture them (or price)? They've been around a long time now so I can believe they would be.
They also make sense from a hygiene perspective, the less (humid!) stuff everyone touches, particularly after they washe their hand, the harder it is for bacteria to spread.
I hate those things: like everything Dyson makes they're noisy, ugly, overpriced, underperforming crap. I must admit to being slighly joyous at finding they're also something of a health hazard: sort of the icing on the cake of a terrible product.
If you can believe it, the Dyson Airblade V is even worse: it dries your hands by the clever trick of blasting the water from them and spraying it liberally over your trousers along with the wall and floor beneath the dryer whilst making enough noise to wake the dead. Total junk.
EDIT: And don't even get me started on the stupid Airblade tap/hand dryer hybrid. What a travesty of innovation. Got large hands? Prepare to confuse the thing as it can't decide whether to douse you in water or blow a hoolie. Talk about a solution begging a problem.
I would bet money that the motion-sensor toilets are not cost effective in the long run. I have seen way too many of them in some kind of malfunctioning or non-functioning state, and I don't think just any random plumber can work on them until/unless they learn specific manufacturing details, which involve electronics and sensors (not your typical plumber stuff).
I would never spec these in new construction unless they were the kind with a purely mechanical flusher incorporated as a failsafe.
