If you can set items up to spawn in and then de-spawn a second later, couldn't this be used for animation?
By that I mean, for simple example, have a large rock spawn in one spot, then de-spawn, and have a duplicate spawn in another spot and also then de-spawn, and repeat the process until the rock reaches the desired position? In other words, Key Framing to create a animation. It'll be a pretty slow animation, but a animation nonetheless.

Apart from machinima purposes, it'll add some unique features to maps. Provided the item count doesn't cause lag. Something similar (but clearly not on the same level) as Trails Fusion.

This is the video that got me thinking about this: