The biggest problem that people have with conventional wood beams is that they are both heavy and hard to maneuver. That can make installing them quite difficult and unpleasant. Also, they can be prone to moisture and cracking, which will weaken their structural integrity and require repairs sooner than you would like.
Box wood beams, on the other hand, are lighter due to their being hollow, and are less likely to fall prey to moisture and cracking. They are easy to install and can give your home a luxurious look. These are great investments.