Several reasons come to mind.
First, computer science owes a lot to computer games. Obviously, the computer game industry has made significant advances in computer graphics, but computer games have also made contributions in other areas such as human computer interaction and computer architecture. In the future, I believe the contributions from computer games to computer science, and vice versa, will be even more numerous. Computer game companies and software and hardware companies are forming alliances in order to leverage off each other's research. Entertainment companies and telecommunication companies are also joining these alliances.