@nprofile1q... not really, the only thing the server is needed for is if you want to open the link in the server, they take down the server now then the links are not worse than signal's sgnl:// links or telegram's tg:// links

in fact, the delta chat invite links are just openpgp4fpr:// links, if you go and open such a link in the browser you will see that the "open chat" button contains the actual openpgp4fpr:// link and you could just copy and share that or just share the QR image