This is an artistic choice with a variety of film precedents. Its not exactly the same thing, but if you watch this GDC talk about the way that Arc System Works uses 3d to simulate 2d animation, it gets some of the ideas across:

https://www.youtube.com/watch?v=yhGjCzxJV3E

Artists might want to produce a lower framerate just to make something look filmic (eg, 25 frames per second) or hand animated, but it can also be a deliberate stylistic choice for other reasons. Eg, the recentish Mad Max films used subtle undercranking to make action scenes feel more intense, and part of that effect is a more noticeable frames and I think there is a bit of that in the Spiderverse films too.