The Blocklist and Allowlist define who can and can’t connect to a specific device.
Access Control for both incoming and outgoing connections defines what level of access a partner should have when connecting to a device, or what level of access someone should have when using a particular client to connect. The options range from having complete control of the client, to only being able to view what’s going on, to no access at all.
If you have certain clients that require stricter access, such as a sensitive server, or certain devices that shouldn’t be used to establish connections, like public-facing kiosks, this is where you would set those policies.