The music is the same as Enix's old version, i.e. MIDI and not nearly as good as the original PSX music. There's a mod for that though - google Ficedula's music patch
Guess the use of MIDI is what you do when the hardware doesn't for sure come with support for redbook audio.
It had nothing to do with a 'lack of redbook', especially given the PC port shipped on disc and no one was releasing stuff on floppies anymore. It simply was common for Japanese computer games to support MIDI modules, even into the late 90s. They kept at it longer than Sierra!