Maybe it seems like daycare because, in a sense, it does serve the function of allowing parents to work. That doesn't mean it's an alternative to daycare. The parents want their kids to have an education, but they also count on school to be able to work.
Even here in Canada, if a school has a snow day and an employer doesn't, it can be a little tense if you don't have anywhere to put your kids. People with relaxed employers and good leave options are fine, but many people don't have that.
Why would it be similar in Japan? In Japan, children walk themselves to school (using public transit if necessary) as young as 6 years old. It's not like the US where parents can be thrown in jail for "child neglect" if their children don't have 24/7 adult supervision. I imagine that Japanese schoolkids can just stay at home if the schools are closed.
And today Seattle area high school is already closed due to suspicion of coronavirus:
https://www.foxnews.com/health/washington-high-school-closed...
Of course the poorest will be least likely to be told to stay home (grocery stores will still need to be open - and probably need extra staff for sanitation)
Without schools providing breakfast and lunch many kids will not get enough nutritional meals a day.
When the Chicago public schools "closed" during the teacher strike, the non-union staff were still working to keeps the schools open just to provide meals and a safe place for kids to go during the day.
I expect that our School ALWAYS care for my child. :P
The care of the kids has always been the priority of great teachers in my experience
How is school "used" in other countries, then?