>We don't need to move lettuce production into buildings, mines or submarine farms.

Food crops in general absolutely, some like lettuce could actually benefit from being done indoors though as you could limit exposure to things like E. coli compared to traditionally grown lettuce.

Growing in a largely enclosed system also allows you to prevent runoff, use the least amount of water possible, control all environmental variables etc BUT unless we suddenly develop fusion today and magically start bringing hundreds of fusion plants online a year, using the sun is always going to be more efficient than grow lights.