Since Austin said that it was going to be easy for this to be dealt with, then Samuel did not really have to be that worried.
He might have as well used the money that he could earn by killing many monsters in the peak stage of the nine star rank, in order to upgrade the lives of the kids together with William, but he did not do that.
If they just got the resources, without any form of power to protect it, then they might end up being in danger instead. That was not something that Samuel wanted them to experience.
It was due to this reason that Samuel decided to use Austin in order to do this. As long as it was a large city that was involved, many people would definitely be intimidated, and they would not dare to take any action against the kids and William that easily.
Additionally, it was not as if the resources had to be sent to them in one large batch. Instead, they could send the resources slowly, according to the needs that they had.