Because of (probably) historic reasons passive agent is called just "agent" in most places. Active agent adds a clear term "Active" somewhere.
This can be confusing for new users to figure out that "Zabbix agent" means - passive agent.
Some places where such details could be added:
Item type selector:

Interface name:

And in agent config:
Server=
Could be renamed to:
ServerPassive=

Similarly as it's named for active agent server address.