Rigid Boxes are a fairly new category of paper board based packaging that have taken its functional form only in the last decade. While the basic premise of a rigid box is that it is always firm in form, there are newer developments that have allowed folding flat and hence can create its rigidity “on demand” during packing and shipping.
Why we need rigid box packaging at all is a question that can be answered instinctually when your product is fragile. In the evolution of the eye, Charles Darwin points that the cornea needed protection and the eyelid is created as a basic protection (against dust and fine grained particles) while the firm protrusive skull behind the eye lashes creates a functional rigidity to protect the entire eye inside the eye socket. Likewise, Rigid Boxes, with carefully engineered interior (with foams or other protective materials) beautifully morph out of shape on impact to absorb shocks as a sponge and hence protect delicate items like glass inside.
Fragile products by their very nature of needing protection is complemented beautifully by a packaging which cushions it inside. Bit flimsy, disposable packaging like folding cartons cannot do much to protect delicate products. Most packaging printing companies cannot print or finish boxes in excess of 300gsm. This causes a strange conundrum where customers question themselves and decide whether the strength of their own product must be increased. This is unnecessary. It must be the packaging that serves the product and not vice versa.