Tried 'em. The compression can feel good. And they're handy for holding ice and heat packs. But otherwise they do little or nothing, far short of the hype and claims by vendors who are mostly fleecing Medicare/Medicaid.
As an OSHA safety inspector years ago we used to see employees wearing back belts. Made no difference to us, OSHA didn't recognize them as legitimate safety equipment because NIOSH and other studies showed no benefits.
There are some custom braces that, like neck braces, can provide needed support after some types of surgery, or folks with serious spinal problems. But we can't buy those from Walgreens or through those late night TV Medicare/Medicaid hustlers.