Why is Bostons’ Museum of Fine Arts doing, traveling a show to the casinos of Las Vegas? “What even the critics can’t deny is the appeal of the paintings. So far, the Bellagio’s Monet show has been a smash, drawing 18,000 people in the 10 days after its Jan. 30 opening. At that pace, and with its $15 ticket price, the MFA could earn even more than $1 million – the total figure hinges on attendance – by the time the show closes in September.”