MP3 is still the standard lossy audio format. Plays on everything, patent-free. OK sound quality (some stuff falls apart even at 320 if you have golden ears).
Especially in podcasts where it's just voice the savings in storage and traffic are significant. My own listening preference is 32kbits opus at ~1/4th size of the original 128kbits mp3.
32 is more than enough for books/podcasts, 96 is more than enough for music. I doubt above-96 makes much sense for OPUS - I'd use FLAC if I needed better quality.