Good question.
Let's say you have your corn in cold-storage. You transact, send, receive, etc. Maybe you are a bitcoin treasury, maybe just someone that wants to not have your IP associated with your wallet.
If you check a public node, your IP goes with that check and now someone knows you are associated with that wallet and what your IP is - admittedly almost as good as a physical address these days.
If you check YOUR node, no one knows anything. If you run your node over TOR through a VPN with no logs, not even that.
Also, you support consensus.
You can also run a Nostr relay on your node. That is my next project.
Lightning nodes can also be configured. I think that will be later, assuming I'm around.