I've never had a set of slicks that wore evenly when left alone. So now I swap them after every weekend of racing. Extended life of the pair.

Some slicks/compounds can also start to "feather" across the tread. When this happens, it can reduce traction a bit. Reversing them can "clean" this feathering off for a while.

Your car looks to be hard on sidewalls, swapping slicks from side-to-side or not. If sidewall distortion is excessive enough, the distortion can extend into the tread area too. I run a rim at least as wide as the slick so I can run additional air pressure while still maintaining a wide contact patch......and reduce sidewall flex. I have 9" Hoosier radials on a 10" rims, running 21 lbs of air. But each car/suspension/weight/tire combo is different.