A celebrity endorsement of any product is almost always a good thing.
When a company can illustrate that it's products are being used by hip, trendy celebrities, sales flourish.
See for example Dr. Dre's Beats or Louboutin's boots as prime examples of this.
So it should come as no surprise when the Valentino fashion house made note of the fact that actress Amy Adams was spotted with one of its bags from their 2014 spring collection. But, it was the location of where she was spotted, that was the issue. Ms. Adams was attending the wake of friend, Philip Seymour Hoffman. I think that's all that really needs to be said. Poor form, poor form.