The contract thing is not cut and dried tho, understandably, on the agency's part, there are often clauses in the contract where the model must book x amount of work in the 1st week or couple of weeks or they are sent home..it's not a guarantee, and I assure you, many girls/guys are sent home.
Also obviously you can earn over your contract amount also.
The best thing about it for many girls is the experience, they will work a lot and learn a lot if they are newish, but the tears are often not great, and also that the girls will come home with a tidy lump sum, that can be invested or whatever which is better than the usual 6 months later drip feeding of job payments that is usual in the industry!
Also it is a good place for a reality check for girls who are doing the job for glamour and fame haha.. the hours are long and hard, the accommodations are small, the competition is tough and many girls get homesick and find the culture shock difficult.
but as a first overseas destination for new girls it is the best (if your look suits) as they reaally look after the girls, drive them around etc and it is very safe.