Point of thermostat?

I put a thermostat in my sims' house, but I also gave them the Acclimated to Cold and Heat traits, so they have never complained about feeling cold in winter, as long as they are indoors (this is in Brindleton Bay). They must be feeling something, though, because I have noticed that they will go and light the living room fire first thing every morning and that they spend a lot more time in that room than they used to, sitting in front of the fire and reading or watching TV. They also seem to drink a lot more hot tea -- maybe it has the same effect as cocoa? I love all this, because it seems so natural and homely, so I haven't wanted to interfere by turning up the central heating. I haven't gone through summer with them yet (I'm still in early spring), so I'm not sure whether I will need the thermostat then. If not, I might just take it out, although this would be rather a pity, as they have accumulated way too much wealth and I was (rather perversely) looking forward to a new way for them to spend it.