Todd Stock
Virtue: conformity to a standard of right; a particular moral excellence; a beneficial quality or power of a thing

Virtue Signaling: The conspicuous expression of moral values by an individual done primarily with the intent of enhancing that person's standing within a social group.

In this case, the OP's ask was: "As the caption says, it interests me to know how to enhance the design of a piece so it is OBVIOUSLY (emphasis added) made with hand tools. What makes it look like it didn't roll out of a machine shop?"

The key here is the judgement by the OP (and most of the rest of us) that handmade is superior to not-handmade (hence, "...enhance the design...") and what signals that superiority. In this context, virtue signaling is the adjustment of a design to emphasize some element which tells the audience that the object is possessing greater excellence (or virtue) as a consequence of its obviously handmade nature.

Virtue signaling comes out of general signaling theory, but it is an interesting way to look at choices in design, materials, and methods of execution.