So some of you probably noticed the crosspost to nostr checkbox now available on the post form uder the options dropdown

hitting the little i we get the following message on a popup:

crosspost this discussion item to nostr requires NIP-07 extension for signing we use your NIP-05 relays if set otherwise we default to these relays:

The same checkbox is available on your settings page, so you do not have to check for every post you publish on SN.

After placing a npub on the profile setting page, no custom relays added (we trust SN team has selected the best ones for us). After publishing a post it's still not appearing on the nostr profile liked in the setting page. It's actually possible to post having only the npub? or it's used only for attribution purposes, meanwhile the post is published somewhere else in the nostr protocol under another "publisher"? There's something am missing, but not sure what... can you help us better comprehend what's going on there?

Thanks