With Hilton you get a big amount of bonus points when you sign up with their (free)HHonors Amex and Visa.
There is something called thank you rewards Citi banks they have free CC with bonus points it 1$ for 1 mile on major airlines.
I never cashed any points yet.
HHonors was not really useful for last minute booking when I was stuck at an airport bt it can help if you plan in advance.