The use of the knees and elbows has always been part of kung fu arsenel (espacially in wuzuquan). The impression of the public is that the knees and elbows are reserved only for muay thai boxing. And whenever they see kung fu using those techniques they dismissed it as "imitation" by kung fu.
People who really understand martial art knows that superiority of styles boils down to understanding ones martial art style and training properly.
Kicks in wuzuquan are mostly targetted below the waistline. Front kick, sidekick and round house. The most common targets for kicks are the rib area, the groin, the thigh both inside and outside and the knee.
These kickis can be found in wuzuquan forms such as di st'st, sa st'at, si st'at, and song sui.