That's exactly why I have and use one. I have a more convex edge for cutting thick wood, and a finer edge on the other bit for smaller work (trimming, twigs, branches, etc.). I don't keep either bit slicing-sharp, but they'll certainly cut paper.
Safety is a concern, but if you obey the groundrules for single bit axes, you should be okay with a double bit axe.
The history of the double bit goes back probably quite further than writing. Definitely, here in the US, the double bit axe enjoyed its fastest popularity in the West-to-Northwest, where the trees were bigger and it made sense to have two edges: one for big tree felling, one for smaller tree felling. Since then, it's remained as a viable extension.
I also keep a smaller axe for smaller work (and a maul for splitting), but the double bit--with its 3/4 handle--makes short work of big tasks.
