I used my belt for squats last night for the first time. I am a believer now. Being able to expand my abs against the belt gave me tons of support. I don't know how to explain it but i was able to stay upright better in my heavy sets. I tend to lean forward after several reps when going heavy. This really helped me focus on controlling the movement better and I could really feel my glutes activating.
So if for anything else, I appreciate the belt to help maintain my form.