Centralised Auth stack for all your services.

I for example just put together a neat pocketID+Crowdsec+Caddy stack, and via OAuth I can easily manage everything. Every service that integrates with OAuth makes it super simple to create new users automatically with limited scopes, all directly fed by PocketID, allowing me to expose my services to the open web without fear of being hacked (crodsec being the fallback if shit would hit the fan, blocking all the community-sourced known threat actors and suspicious behaviour like port probing, login stuffing, etc.).

I like OAuth for simplifying my login process mainly. I use Authentik for a lot of my home services (calibre, nextcloud, freshrss, etc), and not having to deal with Plex's authentication service would be awesome. In fact a few months ago my work started blocking Plex, not my home domain though so I can access the webplayer but not login now (so no more morning local news in the background now that I'm back in the office).