I don't have a belt/edge sander. I've made a PILE of bows of all types without one. I've carefully weighed the tool purchase decisions I've made so far, and the edge/belt sander has always been down the list a ways. Now that I'm tooled-up pretty good, I thought about maybe getting one, but I honestly don't know how much I'd use it. A lot of my bows are snakey, lumpy osage bows and all their bellies are radiused, so...
Even when the bellies are flat and straight, I won't tiller with a power tool. By the time a bow approaches my tillering tree, power tools are silent and still. I'm not in a hurry and I like working with hand tools, especially good sharp rasps and scrapers. To each their own though I guess. It's all bowmakin, so it's all good.