As @Volusiano said: it depends what you’re looking for. I derive a lot of pleasure from streaming my music directly from my iPhone to my More1s. The sound is just as good to my brain, when it’s just looking to hum along with Norah Jones and rip off a few of her guitarist’s tasty licks, as listening to an iPod (okay - that’s not quite true, but close enough) …
However, when I was still active in the studio, I wanted to make sure when I was laying down tracks that I could hear and “feed off” the sounds of my fine Gretsches, Gibsons, Martins, Fenders, Taylor, etc. After all - those sounds are the reason why I shelled out so much coin to acquire them. Only phones-over-aids work to deliver that quality of sound to the hearing compromised musician.
Non-players, IMO, will never feel the same drug-like rush as a real player who’s caught up in the magical, synergistic, existential moment when music, emanating from different spirits, comes together in its own “Big Bang”. But - ya gotta be able to hear it to catch the buzz.
[(Good phones) + (loose moulds in ear canals) + (telecoils ON)] = {PDGFADG}