I recently gave passkeys a shot. For some of my logins, I wanted to enable it to familiarize myself with the feature. Apparently, the desktop application does not support this. I added a passkey to my Discord account, and logging in through the browser worked as expected. Logging in to the standalone app was a different story.
Upon choosing the passkey option, I kept getting Windows hardware token prompts, which effectively renders passkeys unviable if a user is trying to log into a standalone app that does not open a browser login portal to handshake with the desktop app.