Most gamers don't even know about DACs / AMPs so to them they only have to compete against other sound cards.That sound card look like its only digital out is coaxial.
While I actually prefer coaxial S/PDIF because it is less fragile then optical, the fact of the matter is, such a connection is becoming increasingly rare on receivers and amplifiers. For that matter, S/PDIF's days may be numbered as it is limited to compressed 5.1 or 7.1 signals, and does not have the bandwidth required for newer versions of Dolby or DTS surround (I notice the newest AppleTV device omits S/PDIF all together, making it's audio out HDMI only).
Of course, if all you are doing is piping out a digital audio signal to an amplifier or surround receiver, you may wonder why you need a discreet sound card at all. The only argument I can imagine is if it takes significant load off the CPU, and with today's multi-core screamers I have a hard time seeing allot of practical return on the effort and cost, especially in exchange for filling up another slot with another card which diminishes airflow in the case. Maybe this is targeted to people without an amp and with analog susceptibility.