Even the motherboards have gotten better over time. I recall being over at a friend's house in the early 2000's and he was saying, "my speakers are so bad, I guess I need new ones" and I said, "wait, try plugging those into a different source", which we had in the form of another friend's laptop. The audio immediately went from tin can quality to reasonably transparent. The issue was with the cheap DAC in his computer.

But I usually go with onboard sound these days. I did get a FiiO E10K when I got new headphones recently, but I've put it away even though the sound is noticably smoother and less compressed-sounding than my onboard sound - it's another cable and associated hassle.

The reason to go for pricier stuff in my mind is to get more I/O. Good audio interfaces for recording can run you hundreds, and you're paying there mostly for having more channels and some recording features. There's more of an expectation of getting what you paid for.