The downside of wood mugs is that they are hard to maintain and clean them if you plan on using them.
Yeah, I love the idea of a wooden mug in theory, but in practice, I can see that being a potential headache. Certainly not something that can go in the dishwasher, and ideally something that would require some nice lemon oil or something equally expensive to keep it in good condition! Sigh, pity all the nicest things are such prima donnas when it comes to maintenance.