Why is Order in Layer not keyable?

Basically as per thread's title I was wondering why order in layer is not keyable.

I was trying to set up an animation where I wanted for the animated sprite to change its Order in Layer in the scene in order to appear in front/behind of other objects. I would have thought this is a pretty common use case, however I noticed that Order in Layer doesn't seem to be keyable in the animation window.

Any ideas why that might be, if there is a good workaround and if there are plans to add this functionality?

Many thanks!