I totally agree with you both on this, every business is prone and open to competitions so if giving out bonuses, incentives or settlements to your customers would make them want to bet on your casino, then why not??
but if the costumer is legit? then they will not totally relying in Bonuses and giveaways instead they will look for legitimacy of the site to provide wins payments.
My only challenge though is the fact that some persons tend to misuse this opportunity, because the know they'll get something at the end of the week or probably month, the decide not to take their betting serious so here's it, I'll rather the bonuses are given to a particular set of persons, maybe to encourage their wins or to those who makes heavy loses or perhaps, a raffle draw.
that's it, it is only prone to abuse and cheating this is why also some sites does not offer such thing to prevent those abusing .