If your left index finger is long enough or you don't mind shifting your grip to operate the bolt release, then it's not necessary. With practice, you can always build speed. The BAD lever is a luxury item in my opinion.
Not useful for me - my trigger finger can reach the original release. It also gets in the way of my ambi mag release, which I do find useful as a lefty.
Lefty hear too. I use a bad lever. I hit it with my right hand after I reload. I've gotten pretty good at it. I wish someone made a fully lefty lower with reverse controls. I'd buy one haha