Yeah, but it's assumed in your question that the answer will be found. That's a pretty big leap of faith.Would you rather your little sister to suffer and die, or many kittens? I'd pick the kittens.
Right. The fact of the matter is that most research is done in vain, leading nowhere, but destroying many animals in the process. We can quibble about whether that's salient or not, but it must be considered in the calculus. There's pretty much no disease research that proceeds by the process presented in the question above. Even though it's ostensibly for kids, I think it's giving children a wrong impression to assume that there are only two outcomes to be had. The world has many shades of gray, and I think even children can appreciate some of them if given the opportunity.