A flattened gasket that has lost its sealing curve is what causes
the surface wear. The hose restores the flex of the gasket surface and not only seals better, but also has less surface contact [ foot pattern] flat tire/inflated tire..
Talc coating is a procedure that Benz recommends on many rubber installation jobs.
I don't believe it is abrasive, but it may be....
I remember using it on suspension bushings and we always used it back in the old tire/tube days..
A good, hard wax was suggested just for extra surface protection...
Edit :
Did some talc research and it is a very fine abrasive. But Tire Talc is the finest and used in the Aircraft industries as a rubber lube..so.. may be good with rubber as a lube , but also good as an abrasive on other surfaces..
??
I think Benzs recommends it for jobs mostly where compressing the part together, as on dry rubber it is slick..[ like the rear axle donuts and such]
??