FIRST Robotics had a brief stint encouraging teams to use the Kinects for something on the robot, or just test them out and see what you come up with.

I remember reading through the documentation and case studies and realizing just how advanced the tech was / is.

Yea that did make me smile also, glad some use still being extracted from the Kinect, it was (and still is) an amazing bit of kit. I suspect they have support from MS for their use case rather thank just hacking it.

I remember this one setup in an aquarium where you could move sand around and the Kinect would read how you have the sand formed and apply geological effects to it.

Pile it high, mountain, carve it out, water and eventually sea. It was pretty amazing as it was all projected into the sand in real time and looked just amazing.

Think it was running on some 1080 or 1080-Ti when that was king of graphics cards.

That's an augmented reality sandbox! You can make one yourself: https://arsandbox.ucdavis.edu/

A lot of local science centers / children's museums have this kind of setup somewhere, and more often than not, I've seen a Kinect hanging out somewhere doing the topographic mapping.

GPUs formed the backbone of machine learning. Gamers moving society forward :)

It's a versatile piece of hardware! As long as you're not trying to get granular object detection less than a foot away it's able to see features with a fair amount of detail.