I'm puzzled as to why this seems to be a big deal. Lots of people all over Hollywood (and television) have been working on this concept for years now.
The 1997 Dirt Devil ad with Fred Astaire (footage from Royal Wedding I believe); although to be completely fair, the Dirt Devil ad puts their product into an existing clip rather than excising and recompiling clips of Astaire for their commericial.
In 2005 Volkswagon did that ad using Gene Kelley's likeness (from Singin' in the Rain).
Ford had a commercial a few years ago for the 2005 Mustang using Steve McQueen's likeness.
Perhaps the most notable movie use in recent years may be Laurence Olivier's posthumous appearance in Sky Captain and the World of Tomorrow
(an under-appreciated film if I ever saw one, it would have done better in theaters without Paramount's meddling).
And of course there was Bryan Singer's use of Marlon Brando's image (and lines) for Superman Returns