I still play Sport as much as I play 7 for two reasons.
The first is that the club I'm in, Car Of The Week, is still based in GTS because of 7's abysmal lobbies.
Second, if I'm making a livery for a car that exists in GTS, I will make that livery in GTS and then transfer it over to 7. This not only allows me to use that design in both games, but GTS also has a better search function for decals because of its open API and fan made search engines. It's a pain to search for anything in GT7.