Motion is event-oriented
A sensor may report movement and then clear after a timeout.
Occupancy is a broader state
Some systems combine motion with other sensing methods or logic to estimate continued presence.
Choose the automation to fit the sensor
A hallway light can tolerate different logic from a room where someone may sit still.
Privacy changes with sensing technology
Understand what a sensor measures and whether data leaves the home.
Keep in mind. Compatibility is not permanent. Confirm the current manufacturer, platform and certification information before purchasing, resetting or migrating a device.