A fade is a very simple animation to communicate what's happening, but the details of duration and exponential vs linear transition can make a simple fade seem frantic, soothing, or even invisible. When you say "fade into the background", I assume you mean a linear animation that takes about 1 second. It's pretty awesome that the world has a very specific fade that serves as a "word" in our shared design language.

Interactions are filled with interstitials and microstates, but a fade isn't really appropriate for all of them. While we try to figure them out, some folks will make animations that remind us of geocities - but others are going to express actions with animations that seem so natural we can't help but describe the action as the animation. Just as you did.

And then our shared design language will have a new word.