Yes, you're right, I missed that.
The main difference between AD Query and Identity Collector is the API used to acquire the information.
The reason we need to read the security logs is to automatically associate IP addresses to usernames and machine names.
LDAP is used to get groups, which are also relevant for Access Roles.
Identity Agent can also get the information, but this requires installing agents on the local PCs.
There is also an agent for Terminal Servers.
And of course Captive Portal, as I mentioned earlier (but this is not necessarily automatic).