I Don't Care. Do you?
He's using a CVF Racing pulley set-up. I run the same twin belt system on my car. They make similar for just about any engine. Simplicity of design is likely the reason for two belts. No need to incorporate additional guide pulleys (gain belt wrap advantages) or a tensioner this way. I'm thousands of miles into mine without any issues. Will it cause any? Who knows. I doubt it...but it looks cool!