Not just great for bento box users. I have increased amounts to make family meals and stocked my fridge with lunches we can eat cold or reheat. This would also be good food for a picnic.
Recipes are not too complicated and don't require too many ingredients. I did have to buy some sake and mirin, but at least I have used them over and over. I didn't have to buy a bottle of mirin just to put one tablespoon in one recipe and then have the almost-full bottle sitting around my kitchen wondering what to do with itself.