Tasteful or not, that's a matter of opinion.
Upon Michael Jackson's death, radio stations across the country played all of his music as a tribute. Some thought it too sad to hear it over and over again, so some stations pulled the opposite. Those stations were considered inconsiderate because they didn't do anything.
These ads are Billy's work, his trademark, his legacy. Would you want the last thing you did to be scratched just because you died, or would you like your work continued on in respect for your contribution? Of course, it's commercials and people make money off of them, but don't people make money off music sales and movie/tv shows? It has been speculated that half of Michael Jackson's debt could be eliminated by the explosion of album sales from this past weekend following his death. Who gets the money? Surely, he doesn't.
As a matter of fact, on the upcoming release of Might Putty wood and its advertising, there's a scene of the stuff pulling the "Jolly Roger" from the "Pirates of the Carribean" movies, with Billy Mays on it. That prop ship has been in a number of movies, also featuring classic actors like Marlon Brando. Billy, on the show Pitchmen (where the behind the scenes shots were shown), mentioned he was proud to find out that he would be mentioned among those fine actors because he shot a commercial there. The airing of the commercial would solidify (and pay homage to) that historical moment in his personal life. And, because his personal life is public, he shared that moment with us.