I have a veggie patch and grow most of my food there. As I am in Queensland, I can garden all year round, moving from summer to winter crops as required. For a long time I only ever planted food-producing plants and considered growing flowers a luxury and a waste of space. Then one year I grew flowers in the garden, alongside the veggies, and noticed a significant increase in the yield that year. This was due to the flowers attracting more insects, and in particular bees, to my garden increasing the rate of pollination, resulting in better fruiting of my plants.
Since then I have been planting flowers with my veggies every season. Not only does my garden look amazing, but it is more productive as well.
Once I have a plan, I go to the nursery and get just what I need, with no impulse buying of plants that are not right for my location or season. What I cannot get from the local nursery, I order from the Diggers Gardening Club or another catalogue company. Now that I have experienced the greater abundance that flows from my garden due to the flowers attracting pollinating insects, I will never think of flowers as a luxury again. They are a necessary part of any well-balanced ecosystem and when you plant flowers, you are helping nature to return to that natural balance, that was there before we came along.