Going to the movies was always a habit left over from an earlier time. Of course when all you have is a standard definition tube TV and VHS movies, going to see something on the big screen is exciting. But nowadays, large 4K HDR TV's are cheap now, and you can get almost everything on streaming. Covid really hit the big reset button and made people question a lot of their habits, including still going to movie theate…
A movie in a theater was great for early stage dating. It gets you in a dark place in neutral territory with the other person where you sort of have some privacy but still public enough that it is safe, and you have a good excuse for sitting right next to them.
There you can do things that try to inch up the intimacy but with plausible deniability, such as the classics we've all seen a billion movies and TV shows like hand touching while reaching into a shared extra large popcorn ("it was a better deal than buying two smaller sizes...yeah, that's why we have to share!") or the arms resting on the back of the seat that sort of turns into a side hug.
I don't think that would work with movies at home. It is not neutral territory. There might be parents, or worse, obnoxious siblings around limiting privacy or even actively trying to see how your date is going. For the person who is the guest it isn't as safe as a theater. There isn't an excuse to sit right next to each other so the arm trick is out. You probably each have your own bag of microwave popcorn.