I can't get too much in the details, but it's not something that requires me to be crazy qualified. It's mostly telemarketing and customer relationship management. Considering the customers are foreign-based, that's why the shift is at night. Since many of their customers are big firms, I guess they do need a foreigner who can understand their needs and who they can communicate with clearly. Knowing several foreign languages may be a skill not so easily replaceable though...
About the "treating the employees decently", you never truly know until you're one of them.
I did not know companies can delay the night bonus until the annual bonus. The resulting 6 months bonus wouldn't sound that crazy actually. If it is indeed 50% bonus for night shift, and all I do is night shifts, then I logically should get half a year of bonus (on top of the regular bonus everyone gets). This may psychologically feel "too much" for one shot to the employer (imagine giving an employee 8 months of bonus!!), and he/she may -consciously or not- decrease it to something more reasonable, than if I were to get my monthly bonus.
Also, the no-day-life aspect of that job doesn't bother me. I'm in the right time of my life to do this. I'll do this for now, but I sure won't do it later.
Anyway, so as urodacus indicated, it is an additional 50% over base pay? I will indeed try and make sure the base pay is "normal".