By that order of thinking, its always better to send monies to the native population than to transfer even one Westerner to the area since the cost of their ticket would have been better spent on actual resources.... right?

No!

This is not a humanitarian mission---its a vacation in disguise.

The man clearly wanted to kill elephants. Why he wanted it is of no consequence. It's better to allow him to exorcise this bloodlust when there is a positive benefit to humanity than it to either fester or be released via investment into illegal poaching.