I think the point about girls's education being a public good was made because health care costs are being increasingly socialized. If the girl's children get sick, it's no longer her household's problem but the government's problem.
Governments are to provide access to quality health care by 2030 to everyone , and without financial payments from those who are poor.
The World Bank already has developed conditionality (measurement and reporting system) for this universal health care agenda and will preferentially help countries that accept reaching these targets (universal access and free health care for the poor by 2030). Countries that will be seeking to improve prevention of disease through public health measures will therefore be lower priority for World Bank assistance in health. This drive by the World Bank to socialize health care costs also makes girls' education (regardless of quality, apparently) a public good.