I'm pretty sure I played SP on day one, and something felt *off* about the soundtrack.
Sure enough, they actually patched the music in an update (along with the intro movie and stuff). Before then it was literally MIDI instruments rather than actual orchestration. That's… kind of inexcusable, but I guess it's not really the point here.
The orchestral soundtrack is quite lovely; it made me realise how nostalgic I was for Sinnoh. Those games came out right at the start of my teenage years and saw me through most of my teen years, with BW coming out as I was finishing school.
With that said, while it was nice of them to include the DS Sounds, it's kinda funny how there's not as big a difference between soundtracks as there was with HGSS' GB Sounds, or even between the original RSE soundtrack and ORAS' soundtrack. By the time DP arrived on DS, their sound engine had progressed quite a bit past the GBA, and their sound samples were higher quality. So switching DS Sounds on/off doesn't show an immediate or stark contrast, as much as switching GB Sounds on/off did. But still a nice inclusion, for sure.