I watched Pixar’s “Elio” with the kids yesterday and I could swear there was a step printing effect in a montage.
So I don’t think it’s quite that uncommon. For editors it serves a useful purpose as an effect that feels perceptually different than regular slow motion and adds variety to cuts.
Animations are, or at least were, often animated on twos[1], leading to 12 frames per second.
This was used to good effect in Spider-Man: Into The Spider-Verse where they mixed animating on ones (24 fps) and twos[2], making one character appear more skilled than the other for example.
A lot of cell animations in anime are animated in much higher numbers too than just "on twos". Cell animation was slow, so anything they could do to reduce the number of tweens they would do. Most common is to animate in layers so the most difficult thing to animate, usually the character, is static while background elements have more motion.
You'll get animators pulling all sorts of shenanigans. One I learned about recently is when animating on twos (or threes or fours or...) they'll interleave when different elements move. E.g. character A moves on odd frames and character B moves on even frames. This is the same amount of work but feels smoother and less mechanical when watching it.
So I don’t think it’s quite that uncommon. For editors it serves a useful purpose as an effect that feels perceptually different than regular slow motion and adds variety to cuts.