Hi, i agree with edmundask , also some time its good to grape more customers to the marketplace so the volume in the search sites like google will be increased , so lets say cgtrader is ranked as number 10 between the marketplaces, after few months with the high volume of the traffic increased by the free models will make cgtrader move to be number 6 . and so on
u can get an advantage from the free models , download them and c what others have done .