Q. You have a huge, rarely-queried vector archive where seconds of latency is acceptable. Cheapest fit?
A. S3 Vectors stores vectors directly in S3 with a vector API on top, built for massive-scale, latency-tolerant retrieval. It is the wrong choice for an interactive sub-50ms assistant.
Why? Match the store to the latency budget; S3 Vectors trades speed for cost at archival scale.