To lower the stall speed of certain airframe, i.e. you can fly slower and still do not stall the plane and go to
spin-recovery probelms which is not possible when you are near ground; thus those things are mostly
pretty useful for landing. If the design is goow and size sufficient that could lowr the stall speed with
about up to 17%; i.e. in general increase the eficiency of the flight. Some professionla guys could tell
more for sure what is written in the books for Airplane Desing- definitely it is well studied topic.