With you it's all or nothing!
Well, I understand your clumsy questions better if you were missing any information...of course you need (at least) a thermostat to trigger the cycle.
Optimized, I don't know, but it works... and the consumption of the heat pump roughly corresponds to the losses of an equivalent balloon so yes it's interesting even if the thermodynamic balloons in the shops are certainly more optimized!
I have a friend who just installed a brand new 300L one too, I'll try to see if he can give me some running data. So we can compare...