The going theory on slots is if the picking bonus shows you at the end of the bonus what is 'under' all of the ones that you didn't pick, then it was on the up and up and your picks actually matter.
I've played a few times and it seems to be pretty easy to get to and wondered the same, I've never had a session where I didn't get a progressive picks bonus.
Discussion on one of SD's latest videos about the progressive picks bonus for Hot Stuff.
