why did I expect such a comment, it was an easy pass :D. But you can also google it, even with a "perfectly" adjusted heat pump it is so that a pellet stove runs a bit cheaper/more efficiently in operation (without investment).
But you do know that not everything Google spits out is law? ;)
Even if that were the case...there is still the higher investment (how many years can I heat with that?) and more space requirements as well as some additional costs that people like to forget (chimney, storage, maintenance, electricity costs etc.)
Just let it run? As written...lower temperature spread means better efficiency. Or where do you see the problem?
In my case, the heat pump controls the pump pressure independently (direct heating circuit). Depending on the outside temperature and demand, I sometimes have a 2.5 degree spread, sometimes a 4 degree spread (however, a modulating heat pump). The technician from IDM will come again for precise instruction. Does he know what he’s getting into? :D I have to grill him again about which setting has which effect. As I said, I haven’t found a pump setting yet.
...currently again at a 3.5 degree spread, but the weather is just arriving here...at the moment -1.5 degrees