usefulness
noun [ U ] uk/ˈjuːs.fəl.nəs/ us/ˈjuːs.fəl.nəs/
C1 有用性；用处
the quality or state of being useful
Some people think this system of education has outlived its usefulness (= is no longer useful). 一些人认为这种教育制度已经过时了。
Synonym: utility
Opposite: uselessness