The weakest link I can identify here is MITM attacks when you're sending the link. Imagine: Alice generates a link. Sends the link to Bob over an unencrypted/unauthenticated link. Mallory intercepts the link. Generates his own link and send that link to bob. Bob enters the confidential information on Mallory's link. Mallory sees the confidential information, and then sends it to Alice's original link. The only way to…
It's fine to have someone snoop and see the link, as long as they can't change the link in transit.