It almost certainly showed the density of something suspicious.

And if you have something similar that you wanted to get aboard, you could just put it inside a panettone. Certainly sealing it first, and then having it handled by fresh hands at each stage of the sealing, insertion and final sealing process.

Here is where the lack of forethought and rational thinking comes into play.

Objects like this trigger the scan a non-trivial proportion of the time. It's unreasonable to destructively inspect even a small fraction of these. And why visually inspect? An external inspection will only detect the most amateurish attempts at deception. Commercial packaging requires only brief access to common, inexpensive equipment.

So what good was this inspection? It was intrusive and easily defeated.

No one thought through the implications. Or paid attention to what a pilot program revealed about the impact on security.