Hulu releases them as films -- "movie" is in the URL, as you can see: https://www.hulu.com/movie/pooka-fa27e743-0127-4b22-8fa6-06122dfa5a23. If Into the Dark were a series, the word "series" would be in the URL, like Little Fires Everywhere https://www.hulu.com/series/little-fires-everywhere-bce24897-1a74-48a3-95e8-6cdd530dde4c

Why is that a reason to make a 24 episodes tv show into 24 movies? I care more about user experience than what Hulu says, though... Everyone will search it as tv show and, unless you know the name of every single episode, no one will notice it's there as 24 movies... Also, I did a fast check and IMDB has it as a tv show, for example.

Why is that a reason to make a 24 episodes tv show into 24 movies? I care more about user experience than what Hulu says, though...

TMDB goes by the distributor's choices. Hulu is the official distributor, so it does matter what they say about it. Hulu says they are movies; if Hulu listed them as a tv series, then it would be a tv series here. It's as simple as that.