Maybe the lure of going to play with illustrious Aussie fly half Daniel Halangahu was just an offer too good to refuse.
Whilst Kuridrani's decision to leave is a bit strange considering he might not be that far away from playing for the Wallabies, the flipside of that is AAC (Adam Ashley-Cooper) has an absolute mortgage on the jersey at the moment and will be the 13 as long as he is healthy.
I think people underestimate that the lure of going overseas for a year or two isn't just about money. So many young Aussies in all fields move overseas for a period for a life experience (often working for less money than they would at home).
When Kuridrani has an opportunity to do it for more money than he'd be currently earning it could be a pretty enticing opportunity if you're so inclined.