In the '90s we were doing hundreds of thousands of square yards of carpet tile------demo existing glue down over lightweght concrete. The lightweight concrete performs similarly to Gypcrete. From doing research and discussions with experts in the field rather than these products being so much horrible and useless it's more a matter of misuse and misapplication and crappy workmanship. Certainly it had no place in walkways of commercial office space that required heavy rolling traffic for normal operations.
Some architect, designer, GC or end user envisions cost savings and very light use. In reality the actual occupants of the building are not taking off their shoes and carrying one item at a time across hundreds of feet of cubicle corridor to move furniture, deliver mail, supplies and construction activity. When we pulled up the old carpet often huge chunks of the "slab" would be stuck to the back. Also, it was a freakin' dust bowl where both the backing of the carpet and the surface of the substrate just disintegrate into powder.