The trade off, besides the stress points, is that a can opener would not be as efficient. That is mentioned when the author moves on to the cylinder. Furthermor

The trade off, besides the stress points, is that a can opener would not be as efficient. That is mentioned when the author moves on to the cylinder. Furthermore, not mentioned in the article, a cylinder will support much more weight than a cuboid, making a cuboid more susceptible to smashing under load.