“Hearing quality” and features seem really hard to separate. I’d agree one could define a difference but when I look at discussions on this forum many revolve around the quality of the app or streaming. I’m not an engineer, but I believe @Um_bongo (who has an engineering background) stated that some newer features (I’m not sure if that’s right word) require higher voltages. Phonak had different features on their rechargeables vs disposables, but I guess depending on one’s perspective that’s part of their grand plot to eliminate disposables.
Found the post I was thinking of: Continuing the discussion from Oticon More: Rechargeable vs. disposable batteries::