Answered it for me - the Japan season is much shorter, and thus gets him back to the NRL in time for 2nd half of the season. The Japanese clubs would also be much more willing to ‘cut a deal’ which may see a player receive a big ‘third party’ payment. France teams would be less likely to do a 1 year deal too.
So let’s play hypothetical situations.
Dragons were reportedly willing to pay him $1.3m per season, which he declined. Roosters can only reportedly get to around $800k, which he’s declined.
He signs with Japanese club, who media reports/speculation say may be willing to pay him $1.5m for a short season (though there’s be nothing to stop them paying let’s say $1m, but a 3rd party benefactor from let’s say Sydney, could give him the extra $500k). He plays out the season, realises he’s really missed the NRL and wants to come back, but only to the Roosters, so is back for the 2nd half of the season. Roosters can still only afford $800k per year, so he signs a 2.5 year deal. Gets the $400k for year 1 for half a season.
So….
If he signed with the Dragons, he’d have earned $3.9m over that 3 year period and suffer the indignity of playing for the Dragons.
If he’d just signed with the Roosters, he’d have earned $2.4m (and everyone would have claimed a rort due to difference in earnings from Dragons offer)
Or he does the old Japan trick… he gets $1.5m for Japan, plus $400k from Roosters in year 1 - putting him at $1.9m for the year. Then 2 years at $800k, giving him a total of $3.6m over 3 years. And the Roosters get their man, for $800k per year. Equally, the Roosters could give him the full $800k in year 1, even though it’s just half a season, and he ends up earning $4m, so just above the Dragons offer.
Obviously that’s all speculation, but it’s not a far stretch, and certainly not beyond the realms of possibility. The rort is on!