Eg I've just finished watching Andor for the 3rd time, normal speed.
Movies are good for plot oriented stories, with clear beginning, middle, and end.
But they are not ideal for more character driven or lore oriented content.
Long slow burning stories told over many episodes let you really show many facets of characters and also opportunities to hint at a much larger world than what can be shown within 2 hours.
Movies meanwhile had a long time between the next one and so you couldn't get people deeply involved in the characters. However you had enough to pull off a slightly complex plot and so that is what movies did.