Well, it would be rather inconvenient to have to learn an entirely new form of movement, when legs are so deeply intertwined with your everyday actions. For a snake, legs are hardly a concern, but for a bipedal turtle... well, that's an entirely different matter.

[Akechi would also hate to lose his legs, of course. Fortunately, he's in the clear for now.]

On the other hand, growing new limbs is also fairly disorienting. Suddenly, I take up significantly more space than I did before.