It's not about hiding the facilities from locals, it's about hiding them from satellites. Or at least providing enough uncertainty that the enemy doesn't know f

It's not about hiding the facilities from locals, it's about hiding them from satellites. Or at least providing enough uncertainty that the enemy doesn't know for certain how many or which installations are where. More morbidly, in a first strike scenario you want the enemy to waste nukes on actual farmhouses it couldn't tell for certain were launch facilities or not. Then even if no facilities are missed (something you would be hoping for), that's still fewer nukes to be dropped on cities and conventional military installations.