For us (most outings are FL, GA) -
1. Tree debris is a big thing for us, toppers keep it off.
2. Most of the pollen also stays off and therefore doesn't get pulled inside.
3. Helps with the heat from the sun
4. Rain collection on the deep slide is a bit of a problem at times. I have made a 5 foot PCV pole with a 45 degree elbow and another 3 foot PVC section. After a big rain I go out and put that PVC up under the topper and gently lift for a moment. The pooled water flows right off the opposite side and the topper self tightens back up.
I installed our toppers myself so costs were a lot lower than paying a dealership.
So I am a "pro-topper" RV owner - to make that long story short.
