Its a MX/SX technique thats used to scrub speed and stay low on jumps. In RC its mostly for show but works great if theres a turn right after a jump. As far as landing on power....you should be doing that already
I raced 9 yrs in MX and in RC theres no scrub effect but if your already doing it as a habit then keep on keeping on
I would work on corner speed than jumping technique do to the fact that everyone can jump but its in the corners that beats the field
oh and it does work for some correction in the air as well as stated in other post