I suppose you (or perhaps designers) are thinking of interactivity in the opposite order as I am, as though it's a sensible or a necessary step to position some possibly janky animation in-between the visitor/user and what they're trying to accomplish, and it's sufficiently high-risk as to actually cause problems. I initially couldn't think of how some piece of UI would actually ship even though it posed a risk to the user's experience, but now that I do think about it, it's always been a top-down decision, less that of an actual designer; usually it's a bunch of pointless dropdowns or sliders that just weren't given any thought, and engineers or designers were told to do it because 2 weeks gotta go fast gotta ship. There can be some really bad offenders out there, I've worked on fixing them, I just usually attribute that to pointless pressure to build specific things, where implementation details are removed from the agency of their rightful craftspeople.