Mannequins should be available in two sizes: normal and large. The equipment size should scale accordingly. Material requirement should probably scale too.
The main reason would be to use them as monuments, landmarks, display of power and so on.
Even only twice their current size would already be interesting.
"The psychological trials of dwellers in the last times will be equal to the physical trials of the martyrs. In order to face these trials we must be living in a different world."