DVD drives are common enough now to warrant this. And a game like this could force the last people holding out to spend the $25 bucks. There are plenty, though, when CGW did a DVD-only bonus disc kids screamed bloody murder, even though it had 6 full games on it.
This reminds me - I need to find Tex Murphy: Overseer. UAKM was great back in the day. Back when fuzzy FMV impressed the pants off me. Back when I had the time to beat that game in 3 days.