The main thing it provides is temperature, which is important amd not available anywhere else. You could use it to trigger alarms and backup power before steam production completely stops in case the transmitter got hit by a meteor, for example.
I'm using it with the liquid antimatter reactor (a 3rd party mod for SE) to control the fuel pump and to start and stop the reaction. It's a lot more space efficient than adding a steam buffer tank and measuring the steam level.
Maybe some entities would make sense to add to a blacklist (I use a string setting for this in my mod so it's easy to change), but I don't see a reason to exclude every reactor prototype without a burner by default.