So how will this work exactly? Is my MobileGo token a ETH token or a WAVES token?

If you invest in ETH you will receive a MobileGO ETH token. If you invest in BTC, GAME or WAVES you will receive a MobileGo Waves token.

You will be able to easily exchange tokens from each blockchain at a 1 to 1 value at anytime using smart contracts we have already designed.

https://mobilego.io/frequently-asked-questions/