If you have a voucher for free Pizza, do you choose the margherita pizza aka the one with less toppings and the "cheapest" or a more expensive variant that you would like?
You would of course not choose the margherita. I get every 10 coffee free at my workplace, it doesn't mean I go for the cheapest and smallest cup just to be "nice" to business.
The casinos already have made the money from you to give you these offers, and it's not like you are losing money on it.
If they started to be different to customers based on what payment method they used or slot they played and the word got out, the casino would have a reputation problem.
The fact is, all the slots makes the casino money because of the RTP, some slots do indeed have lower RTP and the potential to get more money from a customer is there, but they should definitively not start rewarding customer based on this.
Being on a losing streak is different, and of course receving a free money chip when you have lost alot of money is just nice and rewarding, but that should apply to all players you can lose thousands on a 98% RTP slot too.
Maybe
@Dan.Videoslots can confirm this for VS, do you reward players differently on what payment method they use and slot they play?