Is the Fiio e10k DAC good for gaming?

Solution
Unless you're having a problem getting the sound level to the loudness you want, or your motherboard's DAC isn't doing it for you (ex: distorted audio, buzzing, crackling, popping, etc.) then it would be a useless upgrade.

If you wanted virtual surround sound you would need a soundcard or software which can mimic it.
Unless you're having a problem getting the sound level to the loudness you want, or your motherboard's DAC isn't doing it for you (ex: distorted audio, buzzing, crackling, popping, etc.) then it would be a useless upgrade.

If you wanted virtual surround sound you would need a soundcard or software which can mimic it.
 
Solution
If you want to eliminate any interference noise that you may pick up from inside the case via the other components (like how I can hear noise when using my front audio depending on how I have the plugs situated in the case) or you need more power to drive your headphones then it is not a useless upgrade. It's not all about loudness, and in general the Fiio E10K would provide you with better overall sound quality than your onboard audio.

The HyperX Clouds are a 32 ohm pair of headphones, so they do benefit from some amplification, which the Fiio E10K would provide.