Fast regex search: indexing text for agent tools

I don't understand why their "Instant Grep + roundtrip to us-east-1" is so slow. First of all, the round-trip latency should not be nearly so bad to us-east-1. But second, and much more importantly, the LLM runs in the cloud. Shouldn't you just situate the LLM, agent runtime, and regex index in the same region? Wouldn't that be faster than round-tripping to the user's local machine?