I think the idea is that economically it holds a country back. Even if we have 40% of our workforce able to work from home, for the parents, it's often difficult to get their jobs done if they're minding children in parallel.
However, yes, it's an issue. Countries like Korea have kept their schools closed. Hong Kong continues to have its schools closed. I think they're just starting to reopen, because they have approximately zero cases at this point.
I think places with good public health leadership have done it very cautiously. Kids are the transmitters of infectious disease for many respiratory diseases, even if they themselves tend not to be sick from them.