In modern China, “cáizǐ jiārén” is used less frequently in casual conversation and often carries a nostalgic, literary, or slightly formal tone.
Describing a Couple: You might use it to describe a couple that fits the classic mold, for example, a renowned professor and his elegant, beautiful wife. It's a high compliment, suggesting they are a perfect, almost storybook match.
Media and Art: The term is very common in discussions about historical dramas, films, novels, and traditional art. A movie critic might describe a historical romance film as “another classic 才子佳人 story.”
Slightly Ironic or Old-Fashioned: For younger generations, the term can feel a bit dated as it reinforces traditional gender roles (man is smart, woman is pretty). Using it to describe a modern couple where both partners are, for example, successful scientists or entrepreneurs, might sound out of place. It's sometimes used with a touch of light-hearted teasing to describe a couple that looks like they walked out of a historical drama.