"insurance" in this case is also a savings account. People need to be forced to put money into the system when young and/or healthy so that's there's enough money available when they are not.

If they're not forced to do this, then they won't and people are forced to stand by and watch as they fall ill and due which is bad for the economy and may already disease, even if you don't care about the moral aspects.

There's little benefit to seperating these things out and obvious downsides to them not being mandated.