100% even today. My new Ryzen 5800X build i had onboard sound, swapped it for an external Soundblaster G6 after a week or 2 as was used to an Xonar essense ST.For older hardware, absolutely. On-board sound on older motherboards tends to be quite noisy (often can even hear interference when the mouse is moved around). Also older cards had hardware acceleration, while onboard sound could take 10% of CPU time.
Soundblaster 16 emulation sounds garbage in DOS. I remember it sounding a lot better so the reason ive paid for a Soundblaster 16 full size card