I’ve done a wide variety of lettuces and other greens. Beets, radishes, turnips, both bush beans and pole beans, peas, strawberries, onions, tomatoes, tomatillos, potatoes garlic, leeks, herbs, zucchini, acorn squash, cucumbers, various gourds. Climbing things do well. I prefer cattle panels mounted vertically to electrical conduit frames. (winter squash, cucumbers, tomatoes, peas, beans) Asparagus don’t do well, sprawling plants that don’t train vertically well don’t either. Potatoes, I’ve decided it’s not a good use of the space in the squares. My preference is quick harvest products. The benefit is turning those squares over or things with an extended harvest season.
I’ve done square foot gardening for more than 20 years; I started without raised beds and later chose to use them mostly because it was easier to maintain the paths between them and keep the weeds out. Raised beds certainly aren’t required. In my opinion it’s less daunting to weed a 4’x4′ box than larger areas. Easier to water, too, though since I’ve moved to coastal Virginia I don’t worry about it so much as I rarely have to break out the hose. It is also easier to do successive plantings for the amount of certain things so you aren’t harvesting everything at once. If you’ve got the space for traditional gardening, and have a plan for preserving excess, I agree that is a sound plan. But for small areas SFG is a sound plan that has been around since the early 1980s.