I’m thinking it means that if you have good/interference-free communications between your cellphone and your hearing aids then you will have high-quality-audio and low-latency and everything will be peachy.
But if you have too much interference, or if the hearing aid processor is too busy then the elastic buffer can provide some extra slack to attempt to maintain the state of high-quality-audio and low-latency. If communications problems persist to the extent the elastic buffer is full, then latency has to suffer in order to not drop the connection completely.