Tractor props have the benefit of creating an airstream over the wings which lets you generate lift at lower speeds - this is why leading-edge props are so interesting. Pushers can’t use that bonus feature of the airstream.

I know, but pushers look so much cooler…

Think of the Piagio Avanti, the various Rutan designs, or the Velocity planes. IIRC, they also allow quieter cabins.