Global scale acausal trading, if it's possible in practice (and it's probably not going to be, we only have this theoretical possibility but no indication that it's possible to actually implement), implies uniform expected surface behavior of involved agents, but those agents trade control over their own resources (world) for optimization of their own particular preference by the global acausal economy. So even if the choice of AI's preference doesn't have significant impact on what happens in AI's own world, it does have significant impact on what happens globally, on the order of what all the resources in AI's own world can buy.