A NonO (฿1900), with the addition of a multiple reentry permit (฿3800) provides multiple reentry, plus you are free to choose ANY health insurance policy, from any country, self insure, or have no insurance at all.
So is that why you chose the NonOA, so you could keep the insurance from your home country?!?
Have you looked at the current requirements for extending the NonOA visa in Thailand? You must choose from one of the 14 Thai health insurance companies and hope and pray they will accept your application. Many pre-existing conditions or age can completely disqualify you from coverage. Then what will you do?