I think the reason they are so good at it is they are actually indexing and storing notes on their own server, not just searching relays and hoping they find them.

Correct. And this new gateway relay uses Nostr standards, opening that search up to every dev that wants to add it into their app. It essentially sits in front of Primal and translates centralized data into Nostr data.

This is cool, we need better search.

From the repo: Why "Antiprimal"? The name is tongue-in-cheek - we love Primal's infrastructure! But we want it to be accessible through anti-proprietary, standards-compliant interfaces. This gateway makes Primal's powerful features available to the entire Nostr ecosystem. Do you think the use of this taxes resources for Primal by non-Primal customers? Curious how this will be seen by stakeholder participants on network, or if it even matters and is just a convenience for all. Thoughts?

Sacrificing UX for even more centralization isnt the answer. This is so dangerous, I refuse to use any client that has this implemented