Why keep film grain?

I see all the time people saying they hate 4ks where the film grain is removed. Does it actually change the look of the movie negatively or does it just change it from the original film release because the grain was there?

I would think when a director is shooting an amazing movie, they aren’t thinking, “wow, that was an amazing scene, and the film grain will hopefully make it look even better!”

I assume I’m missing somethng important, but I’d think getting the picture as clear as possible would be closer to the director’s vision, rather than farther away.

I think of it like the lens flair that’s sometimes added to video games to be like the movies. It may make it more cinematic but it reminds everyone they are watching something, rather than being in it or experiencing it IRL. TIA for the input!