We mostly just use ours on trips. It depends. If I have a ton of errands and the kids have been good, I sometimes reward them by letting them watch a movie while I'm driving around town. But that's pretty rare.
I've also used it a few times when I had a sick kid and had to pick up the other one or go to the store. Makes it a little easier to justify not letting them just be in their own bed. But I always feel terrible when I have to do that.
"We played the traditional car games, we argued, we drove our parents nuts, we drew a line on the seat that our brother/sister couldn't cross, we played with toys, made up backseat games, etc."
Some of the things you remember really did drive your parents nuts (how nice to be able to quiet the kids for a couple of hours). My oldest is 7 1/2, so many of the things I remember doing he is not really old enough to do or doesn't have a sibling old enough to do it with. I used to read, but my oldest is almost ready to try reading on his own. Also, we didn't have car seats. I used to stretch out and sleep. Not possible these days. We also used to take out the back row of seats in the van and sit in a circle and play a game. Never gonna happen.
Times change in many, many ways. Go with the flow!