Uncertainty at the quantum level means that you can never know precisely exactly the position and momentum of the most elementary constituents of matter. It's either one or the other. But showing that this and other quantum effects are present at human dimensions would revolutionize our understanding of physical reality. It would mean that quantum bizarreness is present at all scales, and might lead, for example, to an understanding of where the quantifiable, cause-and-effect, Newtonian here-and-now emerges from vanishingly small dimensions.
Guess what? New experiments get us closer.
What should we make of a bridge in two places at once?