I remember cutting an IKEA desk top down one side and discovering the inside was just corrugated cardboard under a few layers of laminate. it was trivial to break by shearing it but in a typical construction where the weight is mostly up/down it was obviously sufficient - until you cut the rigid sides off that is...

While this probably does have incredible Z-axis strength, I can't imagine it being very strong with any kind of lateral loads.

That the construction method of most hollow-core doors in your house.

This design is terrible for desks, they all end up sagging after a few years of use. Their "SANDSBERG" kitchen table is a much better choice for a desk, no cardboard and metal reinforced