Better battery life and both modes can make the audio sound different vs off.
Battery life doesn't really bother me. I get 3.5-4 hours out of mine. The case fully charges them in like 15 minutes. Put them in the case with 10% and in 5 minutes I have almost two hours of battery life in them.
Using my 85t I just feel transparency or ANC mode are required when using them. Being in my office, walking in public, and so on it's nice to hear my surroundings. Then ANC for the other times I need to kill that background noise.
Part of that is because my 85t and Eite 10 Gen 2 are semi-open designs. So ANC is needed more often since they aren't good with passive noise canceling.
The flatter/neutral sound in "off" is probably what the artist meant it to sound like. I am probably accustomed to over-processed modes. lol