Unfortunately live listen is more like a replacement for remote microphones, not the hearing aids themselves. It adds around 70ms latency with a bluetooth headset. This is enough to be very uncomfortable. For comparison, most hearing aids on the market today have around 8ms of end to end latency.

Source: I've built a hearing aid and done extensive latency tests :)

I had a hearing aid app on the iOS app store for a few years, and all I got was whinging about my app not fully supporting Airpods/bluetooth headphones. I had in the app description and on the website recommending using wired headphones so there was no delay, but people don't understand how things work even when they are told point blank. The reason why people don't notice the delay with bluetooth devices during media playback is that media is delayed to sync with the bluetooth audio. When Apple deprecated wired headphones, I called it a day.

Hmm and I also heard John Carmack talking about problems with audio latency in conversations. 70ms is a lot!

I have a major hearing impairment in one ear. Using one AirPod with Live Listen was completely unusable to me because of this latency.

thanks for sharing! what’s considered the lower bound for comfortable latency?

In audio a delay of about 5 milliseconds is the most you can comfortably accept without it seeming really annoying.

Well-designed, expensive hearing aids have extremely low latency, but there are theoretical limit. The more frequency domain processing you want to do, the more samples you need to do it, and the more delay you're going to have even in the best-case engineering.

Smartphones are unfortunately typically not able to meet these kind of specifications. Much longer delays are acceptable in voice communication because you don't hear your own voice and the delayed voice at the same time.

Point being, it really has to be a specialized device designed from the ground up to keep the latency close to the theoretical low limit.