Without porn, the Internet would be a dirty Camaro sitting on the driveway with a family of squirrels squatting in the engine bay instead of an actual V8.
Gaming and porn have a storied history. If there's a PC with Battlefield installed on the HDD, you can be sure there's an ominous folder titled “Finances” just two or three clicks away. The two really should get together (as they sort of had in the past with Custer's Revenge).
Japan has already successfully melded the two staples into a shameful moe beast, but the real appeal lies in crossbreeding a major franchise with everything that excites and embarrasses pious Americans.
Since the US porn industry has no qualms about making porn parodies of every existing movie (still waiting for a XXX-rated version of Girl Interrupted), we'll settle for making our own gaming-equivalent pr0n parody wish list.