Movie then dinner after gives you something to talk about. It used to work better before movies got so crazy long but it's the same concept of any activity paired with a date something to do/talk about when you have a pause in conversation.
Still, how long could a conversation after the movie about the movie even last? "Yeah I liked it, it was funny when that side character said X, and it was cool when plot twist Y happened." 5 minutes later you're back where you were unless you're both film buffs and do a whole critique of it.
I prefer date activities where you can talk about them as you do them. Even bowling sounds more fun than a movie date, to me. But maybe that's just me.
"Yeah! That reminds me of a time I did Y! Let me tell you how that happened"
Movies are a great shared cultural experience that can be a good jumping off point for a conversation.
I 100% agree around actual activities something to really do while it happens. Bowling is honestly pretty good as you can go as fast as you want or as slow as you want. Good conversation going on just keep talking. Conversation slows throw a few while you think of a new topic or one comes up organically. Bonus points as no one expect you to be any good.
I wouldn't make a movie my go-to first or third date in my 20's though, as it's not really accomplishing the goal of getting to know someone and finding a mate.
Now that I'm married? Dinner and a movie sounds pretty awesome...