In the same sense the point of food is to get you full. There's more nuance to it.

Children of Men, good movie, not fun

Some movies are intentionally not fun, because their message isn't about fun things.

Leaving Las Vegas isn't fun.

Nah movies are ranked on a set of objective criteria such variety and use of color, the use of varied angles, runtime:budget ratio, and so on. Technically speaking the best movies are usually produced by accidentally dropping a cellphone from a hot air balloon

I think you should read my previous comment again.

One can have fun watching a bad movie. One can have no fun watching a good movie.

Schindler's List is not a fun movie.

Movies are art, the point of art is to elicit emotion. If a movie does that, it's probably a good movie.

Imo if it's fun then it's good, but being fun isn't the only path to "goodness". Lots of good movies out there that are the opposite of fun

Having fun is always a valid reason to watch a movie. And making a fun movie is a valid pursuit.

Buuuut at the same time movies can be more than just fun and some people really want that.

Expecting a movie to be more than just fun can lead to let downs.

Tl;Dr people take movies too seriously

Dancer in the Dark

No idea why you’re getting downvoted. Did all the lemmings forget how to experience joy? If you like the art, it’s good art. That’s the whole point.