Well, in the first case you're actually enrolled in a health-insurance plan, whereas in the second case you aren't. This solves many problems; for example, ever

Well, in the first case you're actually enrolled in a health-insurance plan, whereas in the second case you aren't. This solves many problems; for example, everyone who visits a doctor's office or hospital can be assumed to have insurance coverage, so those institutions aren't left with the mess of what to do with uninsured patients.