Oh and here's a picture of the little monsters.
"little"....glad to see you have a sense of humor.
The outside kennel I built for my 1st GSD was all pea gravel for all the reasons you cited regarding the video... Anyway...the benefits I found are exactly as stated. Years later I updated a bit and now have pavers in it with a small section of rock for her to squirt in.....gravel is easy clean up as suggested.