Wheel width...going from 9.5 to 10.5 worth it?

I'm currently running 18x9.5 wheels on all four corners for a track only c5. I'm trying to decide if going to 10.5 width is worth the trouble/cost. If the tires are at the same pressure, a tire on a 9.5 wheel should have the same contact patch area as a tire on a 10.5 wheel. Only difference is an overall track width that's 1" wider, right? What am I missing?

TIA