It's actually worse because you take what were 2 parallel operations (washing your hands and drying them) and make them two serial operations, not able to be run in parallel.
Yes, it does upset the balance slightly for people who want to wash their hands, but not dry them, and for people who want to dry their hands, but not get them wet.
Those are the only scenarios where your argument holds, however.
Simply put, you are moving from 2 independent operations to 2 mutually exclusive operations – meaning that 1 sink (in the Dyson case) can only service 1 user at a time vs 1 sink+1 dryer/towel dispenser which can, at a minimum, service 2 users at once (there's actually a much bigger set of time/path calculations that could go in to this, but the simple case is enough to make it clear that your thinking is confused on this.)
Those are the only scenarios where your argument holds, however.