Theoretically you could build a dating app on top of nostr. If you look at how nostr:npub1tm99pgz2lth724jeld6gzz6zv48zy6xp4n9xu5uqrwvx9km54qaqkkxn72 works, where you have more private interactions.

If you think about the whole identity thing, you could build up a web of trust using nostr, and it wouldn't even need to be just a nerdy nostr thing, perhaps a "normal" looking dating app that uses nostr under the hood.