The Adventure of the Cardboard Box - a Sherlock Holmes Short Story

The story revolves around a cardboard box hiding dark secrets, but I wonder what led Doyle to choose such an everyday item as the key to the mystery.

Holmes’s sharp reasoning is impressive, but sometimes his intensity feels almost invasive. How do others interpret his approach in this case?

It's darker and more layered than some of the more straightforward cases. Does this story stand out among Doyle’s Sherlock tales for anyone else?