Evolutionists often assume that the individual components must give the organism some advantage even before all the components come together to begin the beneficial function. No one knows what that advantage might be, but evolutionists have faith that there must be one and that eventually science will discover it.
They believe this because of their commitment to the theory of macroevolution. There is currently no scientific evidence to support the view that individual components without a known function can give the organism some advantage for natural selection to act upon for evolution to occur.