I think I'm changing my view on this. Rest as many as you want in any game you want. The final rounds will become non-serious, more like early prep for next year, but that's the result of finals spots being secured in advance. Similar to some dud games during SOO period.
Will give more scope for betting crimes no doubt but there's plenty of that already.
Teams that finished high have the privilege. Did every team have the same chance to finish high, no because the draw is not even. Very little about NRL is even.
In Panthers case I just realised they're giving up a chance at a home final, but their Penrith stadium is unavailable anyway, may have influenced their decision.
Storm resting players means Manly will likely be knocked out by Chooks, who otherwise would struggle to beat Storm. But that's part of the reason we tried to win more games!! Weren't quite good enough 😡