A couple of interesting links on Deep Sand Beds…
http://www.ronshimek.com/deep_sand_beds.html
https://www.saltwateraquariumblog.com/deep-sand-beds-just-thing-past/
I wouldn't call the YouTube sand bed in the display tank a DSB. It's not deep enough.
The Shimek reference is well known and very old (but still relevant). DSBs aren't new, and are very reliable.