What is the reason why Mulan joined the army for thousands of years?

There are two main reasons why the story of Hua Mulan joining the army has been widely circulated for thousands of years:

First of all, this story conveys the core values of filial piety and family ethics. Mulan couldn't bear to see her father old, her younger brothers and sisters young, and there was no brother to join the army instead of her father, so she chose to join the army instead of her father, which was filial piety and loyalty to her family.

Secondly, this story embodies the quality of loyalty to the country and not greed for profit. Mulan joined the army not only for family honor or personal interests, but to defend the country. This noble spirit has always been praised by future generations.