The practice of students endlessly copying letters, also known as letter tracing or抄写 (chāoxiě in Chinese), is a common method used in education, particularly for younger students or those learning a new language. This technique helps in:

1. **Handwriting Practice**: It improves handwriting skills by repeatedly practicing the formation of letters and numbers.
2. **Motor Skills**: It enhances fine motor skills and hand-eye coordination.
3. **Memory Reinforcement**: Repeatedly writing out letters can help reinforce memory of their shapes and sounds, especially useful in learning alphabets or characters in languages like Chinese.

However, it's important to balance this practice with other teaching methods to ensure a well-rounded learning experience.过度抄写可能会让学生感到乏味或压力，因此结合其他教学方法是很重要的。在教育中使用这种方法时，应确保它与其他学习活动相结合，以提供全面的学习体验。如果您有更具体的问题或需要进一步的帮助，请告诉我！

(Translation: However, excessive copying may make students feel bored or stressed, so it's important to combine it with other teaching methods. When using this method in education, it should be combined with other learning activities to provide a comprehensive learning experience. If you have more specific questions or need further assistance, please let me know!)