ok so here are the 3 technique
Chidori: require decent amount of chakra and fast moving speed(something naruto and sakura both lack) because unlike the Rasengan and Sakura Punch the Chidori is a piercing stab rather than a really powerful hit, it wouldn't be very effective if you can't execute it at an extremely high speed.
Rasengan: require a huge amount of chakra (sasuke and sakura doesn't have this) and very good chakra control in order to execute.
Sakura Punch: require perfect chakra control (sasuke and naruto can't control it that well) in order to focus chakra at the exact point in your fist.
each of them learn a technique that benefit from their strong point, saying one is useless would be pointless because not everyone has perfect chakra control, a large pool of chakra or fast moving speed.