Notably, this is one reason why WoW managed to hit such a wide audience and become so successful. The art design made the game look amazing, but the hardware requirements were so low you could run it on a potato. Its contemporary, Everquest 2, managed to look uglier while being much harder to run.
This is like asking why we need science at all. We might know that obesity is a significant risk factor, but we don't know why and what we could do about it. So yes, it does need explaining. This is a possible explanation and might inspire further research into the topic, in particular preventative or curative treatments.