Apple has a white paper which explains this a bit: To create a 'machine' 802.1X profile (so the machine logs into the network as soon as it comes up), you need to create a configuration profile.
If you configure WiFi via your settings you will create a 'user' 802.1X profile, which means you're only on the network once you've logged in (which would be using your cached credentials). You need to create a 'machine' 802.1X profile, and this is not something you can set up directly from your Mac.
