If the target of the Skuttle is not staying still, trying to jump on it can fail because of its unpredictable movement. I think that can happen even if the enemy unit is slow. On the other hand, I think forgoing the jump would lead to the Skuttle exploding prematurely.
Is the Skuttle jumping ability meant to sometimes involve significant player aiming to hit the enemy? Are players meant to immobilize the target unit prior to jumping?
If the Skuttle could home while jumping, that would remove the requirement to aim, but also enable long-range Skuttle bombardment due to Newtons again.