“1Password stores all your SSH keys behind secure end-to-end encryption, allowing you to access your keys when you need them without your SSH keys ever leaving 1Password.”
Most developers keep a private key sitting unencrypted in ~/.ssh, readable by any process they run. Moving it behind an agent that asks before each use is a real improvement. It also makes a paid subscription the gatekeeper for every server and git push you do. Keys that never leave 1Password also never leave 1Password’s pricing page.