Price of electricity in Finland peaks at 2.35€/kWh today. Keeping my tiny granny cottage warm costs me over 50 euros for a single day. It's negative 25C (-13F) outside.
That massive spike of 50c/kWh at the left looks tiny compared to today even though that's already insanely expensive
Polyurethane is better insulator, doesn't absorb moisture and doesn't require a vapor barrier but is also much more expensive. It's what I insulated my shed with so that I can let it get cold if need be and will not have moisture problems later.