Media discussions online are too often reduced to plot (oh god), arcs, emotional investment, world building and character development. Sure, TV shows have the space to flesh that out more, but this also comes at the cost of other aspects like lyricism. Shows can have poetic sequences, but it's always grounded in the show's diegetic reality. You can't really have 2001: A Space Odyssey or Tarkovsky's Mirror in show format. Even for more "popcorn" stuff, how do you make as show that plays with narrative structure like Memento or Pulp Fiction. I guess you could, but it wouldn't have the same effect. Films work great to explore an idea, and can do so much more freely.
Regarding characters, TV shows have the potential to create long and great developments, backstories etc. while cinema has to create characters that grab your attention from the first second. You only spend minutes to an hour or two with them and you just get who they are without tons of extra information. I'd argue it is as difficult to write a great character that way as in a long format.
Anyway, why not both?