Having the case elevated from the floor keeps a lot of dust outside. A trolley with 2" wheels makes a big difference! For the modern cases with PSU air intake in the bottom I'd recommend a cart with a mesh instead of a solid base - those are usually sold for heavy flower pots.
Yeah had mine sitting on the carpet.

Not bright. I put it on a table now.
I think the case should be hermetically seal against dust and the shell of the box covered with Peltier and aluminum fin coolers.
Or water cooling, but running water lines into an electrical device seems deviant to me somehow.