a better marginal return: it's often easier to work with abstract networking concerns across a system than it is to tease apart often implicit dependenicies in a monolithic deployment.
Do the complexities introduced not have a cost, i.e. are those marginal returns offset by the choice in the first place? Call it "platform debt."
Oh they definitely do. It's just a different flavor and the debt scales differently. Ideally the debt amortizes across the services so you can solve a problem across multiple places. This is obviously really difficult to discuss or analyze without a specific scenario.
It's probably not worth discussing unless you're actively feeling either perf or coupling debt pressure.
Do the complexities introduced not have a cost, i.e. are those marginal returns offset by the choice in the first place? Call it "platform debt."