They are similar, but not exactly the same for each of the Apple devices that support it.
FWIW, I just ran a little experiment with my AirPods 2 devices. I used iCloud, via my Mac mini, to attempt to both locate and play a sound on them. As I expected, they only appeared in the iCloud Find My app, when they were outside of their charging case. However, they didn't immediately disappear when I placed them back into their case (with the lid open or closed.) What I did find interesting is that they only played a sound when the following two things were true: 1) They were outside of their case, and 2) When both Bluetooth was enabled on my mini and the AirPods were connected to it. Regardless, there doesn't seem to be a clear "rhyme nor reason" on when they appear ... so, I too, am a bit concerned on the usefulness of this feature.