You only have hearing in one ear. In noisy settings, the aids only work when you can hear in both ears. That is, nobody can hear in noisy settings with only one ear: hearing aids are necessary but not suficient.
I guess the same is true for people who don’t use hearing aids at all, and my Moms audioligst says that it’s a brain effect, not the hearing aids, but for my dad, who had some hearing in both ears, the modern hearing aids were effective. The old ones were useless.