Having flowering plants in your garden is NOT a waste of space. Having displays of annuals and perennials that come into bloom during the different seasons will give your heart a lift as they display their beauty and perfume.
Even if you think a garden should be principally for food, you can still have flowers to beautify your yard and to provide visual and sensory pleasure.
The options, styles and choices for building a flower garden are only limited by your imagination. Of course your climate may exclude certain plants, but all regions can have flowers grown successfully.