Nostr and Bitcoin have a beautiful symbiotic relationship. The two don't need one another to survive, but they go together and compliment one another. You can't have the freedom to transact (Bitcoin) without the freedom to communicate (Nostr). Both are freedom tools. Both are decentralized and censorship resistant.

You don't have to use Bitcoin and Zaps, but Nostr helps you understand the need for decentralized money. Once you understand decentralized communication, having a similar money makes sense too.