I don't know anything about animation, but this was an interesting and funny video
he's 100% right
there's a place for hfr - it works really well in a lot of video games - but that's when it's intended
this idea that you "improve" these effects by adding extra frames is stupid - it makes everything look awful - saw someone who did it to the visual effects in jason and the argonauts and the "remastered" version looked worse than the 1963 effects
part of the issue is that smoothing out and adding frames makes everything seem slower - you lose any sense of velocity to all movements - and things don't land with impact when you add frames that weren't originally there because the timing of every movement that you animate isn't always at a consistent tempo start to finish - but by adding frames you even out the speed of a movement
especially on action-y movements it massively reduces the impact of any movement
i also find it flattens the image a ton
it's one of the most frustrating things on modern tvs - but motion smoothing is a similar idea but it makes films and most tv shows look like cheaply made soap-operas (if you haven't turned it off already, i would work out what it's called on your specific tv and turn it off) - it's great for watching sport though