Whatever. Even noting that all the medical trials leading up to humans is because ultimately you want humans in the experiment. That doesn't prove my point, but it's just a bad example.
If you don't like humans in the experiment, I'm sure the scientists involved in such an experiment would disagree with you. I think you miss the power of "coolness" on scientists.
Scientists like "cool" as much as anyone else. But "cool" is not a scientific reason to do something. And a human personally experiencing something does not give a scientific advantage.