Comment by sophacles

* not every task is waiting on the inference. lowering latency on other, serial tasks, can still have a noticable effect. Login, mcp queries, etc.

* data transit across the world can be very slow when there's network issues (a fiber is cut somewhere, congestion, bgp does it's thing, etc). having something more local can mitigate this

* several countries right now have demented leaders with idiotic cult-like followers. Best not to put all your eggs in those baskets.

* wars, earthquakes, fires, floods, and severe weather rarely affect the whole planet at once, but can have rippling effects across a continent.

And frankly, the real question isn't "why spread out the DCs?", its "what reason is there to put them close to each other?".