If you are a gamer or using it for a media center with surround sound and buy the right speakers then it is a must. If you are using it for work or general internet browsing, no reason to waste the money.
The onboard soundcard is a size of a penny, the real one is like GPU, needless to say more? I once was shocked, how the bad sound was, till I realized, it switched to onboard, not to mention EMI. Speakers, headphones matter too.
I use hi-quality headphones to do all my listening. Why would I want a better sound card? (Honest question)
It's like buying a 4k TV and feeding it a 320x240 video source. The ideal output only happens with the ideal input.
