The Master has how many children, again? More than can be conveniently counted. I doubt he treats them as disposable, but on the other hand, he's not going to give Beausoliel as much as Agatha would for Gil, as just one example. Also, no matter how long BS has had to prep his betrayal, the Master has been prepping for that betrayal longer still.
I suspect it's for the benefit of Beausoliel, and whoever else winds up benefiting is a side effect.