I’ve noted that the core of 通 contains 用. In fact, these two kanji team up in the following whale-fish compound:
通用 (tsūyō: popular use; circulation; to pass as)
to pass for + to use
Here’s a sample sentence:
大学生として通用します。
Daigakusei toshite tsūyō shimasu.
He passes for a college student.大学生 (daigakusei: college student)
important + educational institution + student