If using batteries:
Takes a measurement every minute
Updates the display only if the temperature changes by 0.2°C or humidity by 3%
Sends data to Havenwise only if the temperature changes by 0.5°C or humidity by 5%
Sends an automatic update every 2 hours, even if nothing changes
Waits 5 minutes between readings to prevent self-heating
If plugged in via USB:
Takes a measurement every 5 minutes
Updates the display every 5 minutes, no matter what
Sends data to Havenwise every 5 minutes
In short:
Using USB power gives you more frequent and consistent updates (every 5 minutes).
Using battery power saves energy by updating only when something changes.