But if you don't stay, then what's the point in getting their favor? They're staying in the grove, they're not going to be of any use to you beyond the grove and you're not going to be of any use to them since they already have the thing they want. Aiding them gains you the favor of a group that's sealed themselves away and isn't interested in interacting with the outside world anymore. Though fair enough, they could offer to give us insight on our tadpoles to get rid of us. But helping us against the absolute? I don't think for a second they'd do that since again, their whole thing is isolating the grove and themselves.
Also, I feel like Kagha does offer to pay us. Am I remembering wrong?