In theory it sounds like a great deal for the imperial center, but the system also requires high tariffs on all goods produced outside the empire to preserve the privileged mercantile relationships. If the same goods are cheaper imported from a different part of the world, then consumers would pay more despite all the self-important optics of being the "dominant" colonial power and presumably benefiting from the exploitation of their clients.

This helped produce the huge "imperial preference" controversy within the Conservative party in the late 1800s and contributed to the rise of the Liberals. Hardliners like Joseph Chamberlain refused to bend on external tariffs, so disaffected Tories like Winston Churchill defected in advocacy of free trade/cheaper goods being more important than blindly "pro-Empire" economics that were no longer competitive in the global market.