sure, but you're also kind of setting the precedent that random famous people's opinion on things they have no expertise on matters, which probably isn't good for debunking things in the long run
As to the why, it's probably related to social status. In the old days people paid attention and listened to the people with status (who usually became leaders), nowadays with celebrity culture it's somehow inverted, a good looking person who can act or sing gets put on stage, and they get the attention (for singing, acting, or looking good), and they gain status.