I intended to do the workaround for PIN screen to come up while using Vanilla GC was to find out for myself it it will go through as payment for >$50 as debit purchase. That experiment satisfied my curiosity that only transferring funds to prepaids and buying MOs >$50 are the ones that won't go through. I still see people using Vanillas to transfer funds <$50 without issues at the register, it is just time consuming to do so.