What is the origin of the idiom "bright as a button" and when to use it?

The phrase "bright as a button" is believed to have emerged in the English language during the 19th century or earlier. The phrase likely arose from a combination of the qualities associated with buttons and the metaphorical use of brightness to describe intelligence or mental sharpness. This association may have been applied metaphorically to describe someone who is mentally sharp, alert, and quick-thinking. The phrase "bright as a new button" conveys the idea of freshness, vigor, and brilliance in one's intellect.