To the person asking what's the use of this, there are quite a few creatures on mobile that have absolutely no uses at all... but not the kapro. Yes, as you say the sarco is better at everything apart from land travel, but did you forget kapro's stamina drain?. It might not seem much on low levels, but get a pair of lv 225+ imprinted kapros and you'll see. Given enough health and time, kapros can annihilate creatures that sarcos might have difficulties with. Also they're fun to play. And spam lunging in the ocean actually can make it as fast as a sarco.