No, it is the definition of no buffer. Buffer is the excess beyond enough. If you expect some supply irregularities and you don't have enough to compensate for

No, it is the definition of no buffer. Buffer is the excess beyond enough. If you expect some supply irregularities and you don't have enough to compensate for them, that is less than enough - a shortage. Having enough for normal operations (which includes forseeable irregularities) is no buffer. A buffer is what you have in excess of that.