First off they only last two hours and they have drop outs, so using them to ‘filter’ a concert seems pretty silly. Second, filtering a concert is dumb. The only way I’d want to be wearing earbuds through a concert is if there was a mic perfectly in the sweet spot that was broadcasting the best sound possible at the concert and I was out of the sweet spot (pick your seats or spot carefully, a concert sounds very different depending where you are). Mic’ing the concert at the point of your ears, running an EQ over it, then playing that sound 3mm’s away from the mic point is a bit odd and seems like the best way to make the concert sound worse.
If someone really does have a hearing issue, there are products that will last all day that are much better. They don’t have phone connectivity and all that, but they also don’t have those problems.
Personally, my view is that wireless earbuds are just not there yet. The sound quality suffers a lot, battery life is poor, and then there are issues with loosing them and charging them. A good pair of corded in-ear buds would crush these for sound quality, and really the point of having the earbuds for me is to listen to music. Having an 18"-24" cord doesn’t bother me nearly as much as the drop outs and quality ding… and remembering to charge something else…