But how does that have any effect on the work he does as an artist (I am asserting a difference between film and commercial-work)? If he has a bad performance in a film, that detracts from his value as an artist. His "performance" in a commercial doesn't devalue him [as an artist] or any of his work.
it does not change the quality of the work as such, but it does devalue his dedication to the purity of his artistic work and also to his reputation.
if you put the same talent to work selling a telecom company product, it is far less pure when you do it in a film.
if Picasso had decided to start doing paintings for Spanish Communication Company Ads, Spanish Airline Ads etc, it would in fact devalue his artistic achievements.
allegedly, art is about creating art with your talent for that art...a true actor acts for emotions, not to sell long distance plans.
if someone chooses to "dial it in" (pun intended) with their artistic talent to promote a phone company, which they do not even use (how often is Dicaprio in Italy, using this particular service?) it does devalue them in a way, no matter how small.
if that talent is being used to sell you a phone plan, is it really fully real enough to suspend disbelief in the cinema?
Daniel Day Lewis and Russell Crowe do not do ads...they also bring a very genuine quality to the screen because of that, however small a difference.
i can walk in to a movie and suspend disbelief with Daniel Day Lewis...but not with George Clooney, or Leonardo DiCaprio. that does not mean i might not find a Clooney film enjoyable (Michael Clayton was excellent) but there is always a problem for me in watching an "actor" who takes selling coffee to me, on the same level as selling me on an emotional performance.
JMO