Could be...
I honestly didn't knew you couldn't copy music to the PS4.
PS3 and 360 have it (360's music library I deleted years ago and the PS3's library I never use in all honesty), dunno about the One, never tried.
It's so bad, you can't even play audio cd on the system, but you can play USB audio files, just can't copy to the HDD. Just another way ps3 still good even today. That means you have to stick a USB every time you want your own music to play during use.
I try to minimize the time on me PS3, still need to get the compound underneath the IHS replaced.
Besides, far to busy on me 360 still, even tho I got a PS4/Xbone/WiiU/Switch and a fuck ton of other consoles.