1. Delight is overblown, in my opinion. I think most of the people truly delighted by fancy animation are just other designers.
2. It's more useful to think about state when deciding when to animate. Could the user have trouble perceiving the change in state that just occurred? If so, then use an animation to help them visualize what happened. I believe this is the primary reason to use an animation - all others are vanity.
Appreciating delight (for it's own sake) in software design I'd consider a core trait of (old-school?) Apple fans. E.g., lamenting the decline of whimsy in the post-Jobs era.
I don't know of a canonical piece that summarizes this idea, but it's referenced a bit in this short piece https://daringfireball.net/linked/2024/12/05/festivitas
I think there's truth to it being relatively niche, appreciating delight that is, but it's certainly not confined just to designers. E.g., like I'm saying here, a core trait of Apple fans is appreciating these kinds of details.