A decade ago I chose Marriott over Hilton in no small part due to the increased availability of hotels which accepted two adults and two kids. I have had platinum status for most of this period. I research hotels with two double beds (true doubles, not twin beds). If the hotel website does not allow me to enter 4 guests in the reservation, I will call Marriott customer service and ask them to contact the hotel front desk to see if they will accept two kids and two adults in one standard room. Over the years we have stayed at Marriott brands (on points) in London, Swindon, Bexleyheath (don't do it), Amsterdam, Berlin, Budapest, and Vienna. I was not able to get hotels anywhere in Italy, France and the rest of Germany this way.
Outside of Europe we have booked 4 in a room on points with Marriott in Hong Kong, Bangkok, Beijing, Sydney, Brisbane, Costa Rica, Dubai and Hawaii.
I realize four in a room isn't everyone's cup of tea, but it allowed us to travel many places as a family we never otherwise would have gone to.