This tool allows to use pairing (like bluetooth, kde connect, ...) for exchanging public SSH keys, basically as alternative to ssh-copy-id.
With this, setting up SSH authentication is more user friendly, as the user's public key does not need to be transferred to the server manually.
It is arguably also more secure, as no passwords are involved, not even temporarily just to be able to ssh-copy-id.
This tool is design to be used as part of some CLI or TUI, but can also be used manually.