GuestToGuest does not solely permit you to go on a reciprocal exchange: a member comes to your home and you go to theirs; but on top of this you can go on non reciprocal exchanges.
Indeed, thanks to the GuestPoints system you can give GuestPoints to your host if they do not wish to visit your home in return.
This removes the restriction of only being able to go the homes of people who want to stay in your home and allows you to travel wherever you want, whenever you want.
In the end you can continually host people in your home in order to gather GuestPoints. The more GuestPoints you have the longer you can stay in your hosts' homes and the more you can travel to homes requiring higher GuestPoints. The larger a home is or the better its location, the higher the GuestPoints per night for that home.