They can work well, physically and visually, but they are labor intensive to construct as well as to maintain further down the road.
You also have to be aware that traditionally there is always a fire inside the structure that is always drying out the thatch from the inside out. So unless you either live in a desert or plan on having a daily fire for cooking/heating as well as moisture control for the thatch, your roof is likely to have mildew/mold problems and a shorter lifespan.
Cool stuff, but probably only practical in traditional applications.
