A chest freezer supposedly costs about half as much as an upright to run, and new ones are supposed to be more efficient than old ones. I used the freezer to store large quantities of frozen meat and fish, which I got at about half the store retail price given the quality. So I probably at least broke even on the money and saved trips to the stupormarket as well, which were and are expensive in terms of time, money, energy, gas, and above all mental health. Any technology distinguishable from magic is insufficiently advanced. I believe that the reason has to do with insulation.
Freezers have thermostats that work the same way that the thermostat in a house works.
If the temperature falls below a certain point, the heat kicks on until the temperature rises enough, then it kicks off. Same idea in a freezer, just the other way around. The blower kicks on in the freezer when the temperature rises above a certain point. Air is a pretty good insulator, if you can keep it from moving around. Air, being a gas, likes to move around, making it difficult at times to use as an insulator.