When I copy an xmpp uri, starting with "xmpp:", I want to be able to use it as a normal jid for most actions in poezio, (commands, etc.).

As far as I understand and pointed out by jonasw, the only potential issue would be that xmpp:foo/bar is also a valid jid, (domainpart = "xmpp:foo", resource = "bar" (no localpart)), but DNS won't like the ":", and it's not a valid ipv6 either.