Well, they don’t. You’ll have to go to 7/8 with the paddle shifters instead. I’m pretty sure the Corvette is the only car with a standard 7 speed though, and it’s an economy gear at that.
The TH8A can go to 7/8, but only works with Thrustmaster wheels (on the PS4.)
It’s not, not anymore. Simply put, using a clutch and shifter let you shift faster, basically sequential trans speed. Shifting on a controller / paddles was (and still is) abysmally slow. They’ve made it a little faster and outright banned shifters from Sport Mode. But you can still see the advantage in single player and online lobbies.