#KNX
pine solar
You can configure a knx sensor to have a HA entity representing the value.
A climate entity does show it too, but is rather intended for room thermostats where you can set a target temperature too. (It may also show something with only temperature_address set but I have never tested this).
expose: on the other hand is used to send HA values (states or attributes) to the knx bus - eg. from other integrations like Hue or what have you.
Expose is an knx-specific feature. It's more or less a shortcut for creating an automation that does the same with the knx.send service.
delicate oak