When you explain how relays work to a new user, it helps to illustrate how the decentralized protocol works.

Since each relay contains a different user graph, having more relays means you are able to see more content. Some users overlap on multiple relays, but if you don’t share any relays with another user you won’t see them at all.

Every relay is a different window into the #nostr universe, and adding (and paying for access to) multiple relays is how you allow your social graph and the entire network to grow.