I think Nostr clients will build search using nip-94, so the gifs don’t need to be stored on nostr.build. @lemon is just backing them up there while also creating nip-94 events. Clients could build a gif search using tenor or giphy API by using a proxy which I think solves the privacy issue, but with nip-94 we’re not reliant on these APIs where the service can ban or rate limit you at any time.