usefulness
use‧ful‧ness /ˈjuːsfəlnəs, ˈjuːsfəlnɪs/
noun [uncountable]
usefulness of
There are doubts as to the usefulness of this approach (=it may not be useful).
As a commuter service, the ferry has outlived its usefulness (=is no longer useful).
use‧ful‧ness /ˈjuːsfəlnəs, ˈjuːsfəlnɪs/
noun [uncountable] Word Family: noun: usage, use, disuse, misuse, reuse, usefulness ≠ uselessness, user; adjective: reusable, used ≠ unused, disused, useful ≠ useless, usable ≠ unusable; verb: use, misuse, reuse; adverb: usefully ≠ uselessly
the state of being useful or the degree to which something is usefulusefulness of