The benefit of multiboxing is either doing transmog runs or gathering such as Herbing/Mining, since all of the characters can tap the same resource. To me it's relaxing, but it really depends on your server auction house market. This is best done with Druids because they can be in flight form and still tap a node, or if you have to shift out for mining you can quickly shift back in. It takes some practice but you'd be surprised at the gold per hour if you multiple it by x4 or x5.