Basic steering is the stock bellcrank system. It still uses correct steering geometry. The inside front wheel turns more. The outside front wheel turns less. That is normal in a corner.
The difference is servo leverage. The leverage changes through the sweep. Servo load can rise near full lock. Steering feel can vary. Centering can feel less precise if there is flex or slop.
Symmetrical steering is a push pull system. It keeps the same correct steering geometry. Inside wheel turns more. Outside wheel turns less.
The difference is the servo linkage layout. The servo pushes and pulls with equal leverage left and right. It holds full lock with less strain. It re-centers more cleanly. Steering feels cleaner, more consistent, and sharper.