I sometimes dont't like that celebrities advertise a project, they were usually paid to do so, and that does not reflect in the project itself, now if a celebrity advertise on its own, due to actually liking the project, then that is different, but any celebrity will do that, because they have a lot to gain by charging the project itself.
I agree, celebrity endorsements have no long term effect on the project because everybody knows its just a marketing strategy but I'm inclined to having experts endorsing a particular project conveying his own expertise on his chosen field of endeavor.
Instead of celebrities who usually don't have anything to do with health sector they should get doctors, professors on board. I believe it would be much more useful.