Bench shirts are for equipped lifters, and they're bloody hard to put on and use effectively. Takes 2 people and several minutes to put one on.
I don't use them, but all of the other competing lifters in my gym do, I'm guessing if you're asking the question, you're probably not really going to need one just yet.
They do help the lifter to a degree, but require enough weight on the bar that you can pause the bar on the chest. Equipped lifting isn't 'easy' at least not in PA.