Yeah, UI animations can be good. The vast majority are bad, and even the good ones are almost always too long. That's why it's nice to have a setting for them. Those macOS animations you mentioned have no settings to make them faster and they are infuriating.
On phones I usually speed animations up rather than turning them off entirely. But on the Pixel Watch the animations are so gratuitous and add so much friction to my use of the watch that I turn them off entirely.
I haven't tried a Pixel Watch, but on phones I find Android animations generally kind of awkward. They too often feel like they don't fully connect with what they're animating, if that makes sense, and the curves they're on are often odd. I could definitely see the appeal in turning them off.
On phones I usually speed animations up rather than turning them off entirely. But on the Pixel Watch the animations are so gratuitous and add so much friction to my use of the watch that I turn them off entirely.