What's the use?
Speakers, or headphones?
Music alone, gaming or movies?
Getting good sound from speakers is lot about those speakers themselves.
Also room acoustics has huge effect to sound quality.
Even top level speakers won't give any even remotely accurate sound in some arbitrary concrete cube.
And in case of surround set both room acoustics and positioning should be good.
Except for EMI, all that has pretty much lot bigger effect to sound quality than how expensive sound card is.
Headphones get rid of those acoustics and space issues, but have their own things to take into account.
Stereo music is easy and really doesn't have any real accuracy demands.
In fact lots of people favour more or less seriously inaccurate reproduction.
But if you want to be able to get directionality in games, that demands lot more.
Headphones should have overall accurate resproduction and no lopsided frequency response with one end missing in comparison.
Also no matter what marketing and "audiophiles" say, headphones can't ever create any true spatial cues.
Those are formed by shape of the head causing direction dependant changes to signal received by both ears from sound source.
Those need to "encoded" in signal itself, which isn't stereo but binaural sound.
And headphones can only reproduce those binaural cues well giving good directionality and even feel of distances...
Or then trash those cues by inaccurate reproduction and collapse immersion to "head in bucket under water" at worst.
Most sound cards have had some HRTF algorithm to produce that binaural sound from 5.1/7.1 surround for over dozen years.
And that's where integrated sound cards are typically very lacking.
Though compared to money people use for parts with bad return for price/limited usage life, good sound cards are semi-free for their long possible usage life over multiple PC overhauls.
