Animations should serve a purpose - for example, gamifying with a fireworks animation is useful if you think that communicates what you want about the product.
Engineers know that rainbow borders on boxes are tricksy to implement but a cinch for agents. So rainbow borders are a loud way to say “we didn’t pay close attention to what we were building when we built this” - or to be a bit more kind, “we shipped our first draft”.
It’s just like reading code. Why would you want any distractions?