I planted a Sedum on the allotment a few months ago. Someone had left a healthy looking specimen in a pot in the spare produce box by the entrance to the allotments. Sedums are often grown in gardens, usually the Ice Plant (S. spectabile) or Orpine (S. telephium) or cultivars of one or other.
Generally planted as an ornamental it seems it can indeed be thought of as produce. In his book Creating a Forest Garden Martin Crawford says "The leaves are great in salads, with a succulent texture and mild flavour...Leaves can be harvested throughout the season, though they can get slightly bitter in very dry weather". I will try a leaf to two and see if I concur.
Anyway, whether as an ornamental or an edible Sedums are a great plant for a sunny spot. The leaves are evergreen, the flowers morph from green to pink for a late splash of colour and make a striking silhouette when brown and dry in the winter months. Good plant for bees and butterflies now that not much else is in flower.