They make you buy power tools to cut away the old decking.
They encourage you to work to pay for all the new additions (tools, plants, fences…).
You get a serious workout, without a fitness coach or gym membership.
You get to do something good for the Planet (plant carbon dioxide-breathing, organic thingies).
They create a habitat for wayward butterflies and bees.
They impress your partner (momentarily) with your newly developed DIY skills (just in time abilities).
You get to practice your problem-solving skills and achieve something tangible, if not beautiful to look at.
You get out of doing boring housework like washing, cleaning and cooking.
You become just that little bit more self reliant.