the.com/usefulness
The quiet virtue of being worth keeping around.
means The quality of serving a purpose well or being able to solve a practical problem.
from From Latin uti, to use, plus the Old English -ful and -ness, stacking up to mean full-of-being-used-ness.
Economist's petUtility theory turns usefulness into measurable preference math.
Tool DNAShares roots with utensil, utility, and usury.
Survival edgeEvolution favors traits that prove useful, not pretty.