Of course. If you're a serious strength trainer, they're extremely useful.
Having said this, I do feel the use of a belt can be overdone. I generally won't use my belt on squats until I've warmed-up beyond, say, 455 or 495, for instance.
All dead warm-ups without. Etc.
Like anything, one must train in the proper way in which to use a lifting belt. For a novice to just strap one on yields little if any benefit.
As always, many ignorant and beginner-types spouting off here on Getbig.