I agree this seems to be a solution for a problem we don't see (maybe even don't have).
As to hotliners, I agree it would give them better acceleration after take-off. But I would even try the thing in my thermal glider because I have a different flying style (obviously). After seeing the birds with envy, I tried their method: I climb the glider to 500 ft and level off to low-power slow flight to search for thermals. When I find one the motor is stopped. When it goes down I stop the descent at 300 ft and continue in low-power slow flight till I find the next thermal. I don't know if I could win a contest this way but I like it.
Anyway, the 2-pitch prop would make the drive more efficient in both fast climb and slow level flight.