Could also be used strictly as an acquisition method to lure players in because they think they are getting more value.
I agree with you on this and I'm pretty sure this is true for most casinos that claim that all their games have zero edge (users need to be cautious when dealing with such casinos).
On the other hand, what Mahdi said above is not completely wrong. Although a 3% house edge is not that high and most gamblers would be ok with it, the standard is 1% (at least on the well known casinos).
