I don't know about the "boost of confidence" but they keep my right knee comfortable. "They’re also great for people who have current knee injuries or tweaks, as they help to keep the joint warm and add a nice boost of confidence."
I almost always have some kind of "wrap" or neoprene sleeve on my right knee when I am lifting. The wrap or sleeve may or may not promote heavier lifts--I don't know. What they do provide is "warmth". What I have experienced is that my right knee (on which I have had surgery) is much less likely to ache after my workout if I keep it warm while lifting.
Good advice. Great article.
agingbones