Why is "Adoption of Chinese literary culture" trending?

Wikipedia Overview

Chinese writing, culture and institutions were imported as a whole by Vietnam, Korea, Japan and other neighbouring states over an extended period. Chinese Buddhism spread over East Asia between the 2nd and 5th centuries AD, followed by Confucianism as these countries developed strong central governments modelled on Chinese institutions.
In Vietnam and Korea, and for a shorter time in Japan and the Ryukyus, scholar-officials were selected using examinations on the Confucian classics modelled on the Chinese civil service examinations.
Shared familiarity with the Chinese classics and Confucian values provided a common framework for intellectuals and ruling elites across the region.
All of this was based on the use of Literary Chinese, which became the medium of scholarship and government across the region.
Although each of these countries developed vernacular writing systems and used them for popular literature, they continued to use Chinese for all formal writing until it was swept away by rising nationalism around the end of the 19th century.