The idea is that you host all your pirated media from home, e.g. on a NAS running Plex or Jellyfin, and your home server can stream any of your media to any device (including transcoding it to best fit the device and connection).
Tailscale isn't particularly useful for acquiring the pirated media in the first place, of course.
How is this different to running a Plex server on your NAS and streaming directly over regular internet?
You do not punch holes through your routers firewall. There for it's is more secure as a mesh network.
Tailscale has Mullvad integration now, so it can be used that way too
So the exit node can route traffic through Mullvad VPN?