Same thing with solar panels, people will drop 40k on solar just to save $200 a month on electricity when insulation would have reaped half the savings for 1/10th the price.
People just like buying gadgets.
My all time high electric bill so far was ~$220 for a 2500sqft house when it was 110+ outside for most of the month and I was WFH and keeping the downstairs around 70.
I was really nerding out about solar panels and home batteries for a while and desperate to justify that toy, but I would barely break even before they failed or I needed a new roof. Start with insulation, it’s CHEAP compared to high tech options.
As sibling notes, it can be invasive and disruptive vs. just replacing some appliances in a few days, but it's still more cost effective (and will allow your eventual replacement HVAC system to be sized smaller, netting additional savings when you do that).
Same with 10kWp of solar. $4k in gear plus $700 for electrician. Easily half of paying someone else for full solution.
(Prices converted from nzd to usd).