That is a very good argument. I think we should try to make a distinction between efficiency as the energy put into the system (the system would be producing food) and the energy we get, in one hand, and the efficiency in using the resources of the planet. Food from the supermarket is extremely efficient. It required a definite amount of energy in order to supply all your neighbourhood with potatoes, for example. It was just a truck and just one part of the production of a farm. We received a good amount of energy from the one we used.

But that energy comes most probably from fossil fuels. If we can be more efficient in the delivery of this energy, we can improve what is called the aggregate efficiency.

We can deliver from sources close to us, demanding a bit more energy to deliver 1 ton of potatoes but being able to source this energy from renewable sources. We can do that because the delivery is shorter and closer to us. No need to ship freight or carry the potatoes in a truck for 1500km.

Cheaper fuel also means cheaper prices.

Another way to beat the energy aggregate cost would be that if the produce is micro farmed, either by yourself or by a local entity, is that you can use less fertilizer as the soil is not run to exhaustion. Less weedkiller as you can pluck the weeds yourself. Being in a controlled environment also means less plagues, or if a crop plague comes, less pesticide used. Fertilizers, pesticides, weed killers... All that comes from fossil fuels.