Send a secret that can only be read once
Paste a password or key and get one link. The first open destroys the stored copy, and the server never sees the key.
The key never reaches the server
Your browser encrypts the secret and keeps the key in the part of the link after the #, which browsers never transmit. A stolen backup of this server holds nothing but ciphertext.
Reading destroys it
The stored copy is deleted in the same operation that reads it. There is no second read, no history, and no way to extend a link.