The main disadvantage is that it is expensive
My wife and I rested in Thailand in January 2013, at the Plumeria Hotel, we purchased a ticket, like everyone else, voluntarily-compulsorily through a "presentation". It should be noted that, according to the contract, the Alfa travel agency sells you only a place in the hotel, and everything else - meals, medical insurance, excursions, transfers are purchased additionally, which ultimately turns out to be 20-30% more expensive than well-known tour operators.