pointless degree; meaningless qualification; useless license
Idiomatic expression comparing a useless qualification to a grain of rice stuck to the sole of the foot: it must be removed, but it is not enough to eat. Used to describe a degree or license that brings no practical benefit.
Even a qualification you worked hard to get is just a pointless degree if you never use it.
その免許は足の裏の米粒で、実務にはまったく役に立たない。
That license is a useless piece of paper; it doesn't help at all in actual work.
Both describe something valuable that is wasted. 足の裏の米粒 emphasizes that the thing itself is essentially useless or a burden, while 宝の持ち腐れ focuses on the failure to utilize something genuinely valuable.
A Japanese idiom literally meaning 'a grain of rice on the sole of the foot.' The image is of something that must be removed because it is uncomfortable, yet it is too small to be a meal, symbolizing a qualification or license that is troublesome to have but brings no real benefit.