Thanks for the quick reply.
Actually slack, even though it uses the webview for displaying the actual application, when you want to add a new workspace, you get redirected to the browser in order to perform authentication. That’s also true for Talkdesk (https://support.talkdesk.com/hc/en-us/articles/115005728186-Logging-in-to-Talkdesk-Callbar).
My rationale is only that if I was an IdP, I wouldn’t want products with embedded browsers to be using SSO with my service, as I would be putting at risk my own users (although I don’t think there would be a way for me to prevent it)