Because I have used it multiple times in a professional situation and it works. Of course you can't do it when they're burning your hands but that's not when you do it. I have recently adapted it to be even more invisible. I think you'll find if you put some thought and time behind it, the 'pocket switch' has benefits.
you mean that you make them examine the deck, then pocket switch it and do another effect? i do not think that this would work because if you make them examine the deck you will bring a lot of attention on it, so it won't be easy to sneak it in your pocket without them noticing.
but if you mean that you make them "casually" handle the cards, for example asking them to cut the cards, then they will think the deck is ordinary, and without burning your hands. in this situation it can work (and it does work)
what i meant is: the pocket switch is not THE answer. for example, if you do a mental photography routine, when you end it you might want them to see the deck is now printed on both sides. placing it in your pocket won't work. or you might want them to shuffle the deck and then switch it for a stacked or memorized deck. again, it can work if there is time between the shuffle and the gimmicked effect, but then the impact of the "shuffled deck" will fade.