Pocket carry was great against street robbers for the obvious reasons. They expect you to put your hand in your pocket and the 'timer' doesn't start until they realize you are not complying. I've seen almost no robbery suspects pat anyone down or go in their pockets themselves. I think to maintain distance and just a general expectation of compliance.
Obviously not ideal for counter-ambush situations. I think if someone wants to carry two guns, AIWB and pocket combo is a good one where each carry position covers the weakness of the other. AIWB is harder to disguise a draw from, pocket is slow outside of disguised draws, and pocket is excellent for retention so you're not fighting over two guns.