ability to switch is user preferance. I have buddies that have only ihy's in their aresenal, its what they found they liked best and stick to it. Then there are people like me that have ihy's, vv, vw, mechanical, semi mechanical, genesis atomizers, rda's, 510 drip atties, carto tanks all running in rotations.
I say to each their own and as long as they are staying of the stinkies why not. My wife ONLY uses a vamo in shorty mode and a vivi nova, I usually have 4-5 device set up at once, its all in what we like.