You don't need the relays to share files, just to establish a connection with any one of them without needing networking setup or port forwarding etc.

It's about establishing a connection without needing a DNS authority, a middleman confirming identities, or a database of static IP addresses and the like.

It's like LNC but over nostr. You obviously dont need 1000s of lightning nodes to connect to your wallet, but using lightning to connect to your wallet is *way* better than having to use Tor