I was checking out the desert spring model you linked and I don't think it can really control the blower. It can operate without the heat of the furnace but they tell you to manually operate the blower or just leave it on all the time. I wonder how much electricity that would take ? When it's -2 degrees Fahrenheit like today the furnace runs quite a bit so it wouldn't matter much but it's not on so much when it's 30 degrees out.

They also tell you to mount the humidistat to the furnace so it seems like you would be manually monitoring and controlling the humidity.

Could be an advantage though it would be much simpler than the Honeywell one I am looking at would just have to watch it.