@korina It doesn't for me ☺I just tried again, and the layer is not updating as the time slider progresses.
I presume the issue is because I'm using "Ungoogled-chromium", and WebGL in-particular seems to (intentionally) not work, so I think maybe Windy is falling back to some other rendering method which is unsupported/untested by the team. It's not a big deal to me anyway.
It would be nice to be presented reasons for using the 3D mode over the 2D. Instantly the 3D mode felt less useful to me, but it could be because the lack of feature parity.
From this thread I would say the biggest usage would be to properly see the poles.
On another note the "Rain, thunder" layer does not update when "playing" the weather prediction, but this is probably expected. I don't imagine many users will want to use 3D mode except for some specific cases. I would suggest the team to not focus hard on this feature.