Seriously. As a user I can count on zero hands the number of times I’ve said “Oh great, I’m sure glad this UI is animated!” - and likewise zero times have I missed it when animation isn’t used. Animation is a way to light small units of your users’ precious time on fire, for zero benefit.

As the other user alluded to, Animations are not actually there for people who are comfortable using a computer. The vast majority of users are borderlines in capable of using the internet these days. Animations are supposed to be there to really help guide these users into understanding what the scary machine is doing when they click it. Can they be overused, absolutely, but i think have an accordion fold out animated is a reasonable case. You gotta remember your average user isnt paying any fucking attention, so drawing their attention to important changes on screen is not only good but necessary. I'd prefer no animations ever, but i also dont own an iphone while the majority of the world either does or wants to.

Animations are also a way to explain causal relationships between interactions and their results, and to help build mental models of software behaviour.