如何理解because

A 36-year-old female presents to the ED with complaints that she feels weak. She states that she has been feeling more fatigued for several months now and believes her fatigue is worse, especially after working long days as a waitress. She even says that she can’t keep her eyes open to watch television because it becomes difficult to see at night after working.

一36岁急诊女性，主诉进展性乏力数月，且认为其乏力恶化，尤其作为女服务员长时间工作后乏力更重。她甚至诉下班后夜间看电视时候无法睁眼，因此视物困难。

为啥把because翻译成“因此”，“因此”其实与“所以”是一个意思，那为啥把因果关系换了一下

我觉得是“（作出解释）因为”，就相当于“所以”、“因此”，否则逻辑关系理不顺

这种用法与explain如出一辙

“小明认真学习”，“explain解释了”他为啥能取得好成绩

“小明取得了好成绩”，“explain说明”“他认真学习了”

随句子意思，因果关系的逻辑会转变