I have never understood why supposed celebrities influence a decision to buy or not. They are not advertising the products because they use them. If they choose to recommend something, because they believe init,and not because they are beingfinancially rewarded for so doing, it is a different matter.
I still recall, in the early days of QVC, good old Katy John telling us during a fashion show, that her husband did not wear jeans simply because they had a label on them.
I don’t think she was a natural shopping tv presenter, and would find it morally challenging to lie through her teeth about the quality of the goods she presents.