Besides being the best prime time cartoon.
They had episodes where other cartoons wouldn't venture, such as, Fred had a gambling problem, Wilma was actually...Pregnant, Fred suspected Wilma of cheating, Fred thought Wilma was trying to kill him for insurance money,
Barney and Betty adopted a child. There were other examlpes of course.
Did any other cartoon have appliances that talked, prime time or otherwise. They used words that probably went over most kids heads, but the parents probably understood them.
By the time Bam Bam came on board (1963-64) they directed it more towards kids, but it was still a very good cartoon.
They started trends, that influnced other cartoons.
The Flintstones were ahead of their time.