IMO, I don't think it really effects one's effectiveness on the podium. The decibel level of the instruments is well above the level of my hearing loss. I didn't find the performance level of our ensembles were effected at all.
On another note... You can spend $1000's of dollars on hearing aid in a hurry ($5-7K) I bought simple, amplifying aid and am perfectly happy with them ($30 each). I only use them outside of rehearsals, mostly at home in or when I am in offices.