I had a motor bike accident in January. I believe that when a motor bike is registered insurance is required. I know that rental shops include it. I purchased mine and it was included presumably because of the registration. That insurance covered my medical bills, I believe, up to the first 30 k baht. My insurance did not cover the damage on my bike. If I was capable of getting the license number of the Sungtao that took me down his insurance would have paid for the damage and there were too many witnesses for him to have any defense, seemingly so.
In 2008 I was presented with an insurance question. I thought it was a black and white no brainer. I was wrong. When it comes to insurance there are individual differences that dictate comprehensive answers. It is my understanding that generally an annual premium for insurance is $2,500 or maybe 85k baht a year, in Thailand. Many people pay out of pocket, because for them it's cheaper. You do the math for yourself, and look at your own specific situation.
As an American I have access to Medicare. The premium for that is $1377 a year and is tax deductible. I maintain that policy because if I were to have a catastrophic incident I would have access to that insurance. One never knows if or when a catastrophic event would happen.
I know a couple who had a unexpected catastrophic event and it permanently and adversely impacted their lives. They didn't think that insurance was necessary. The husband, at around 54, had a stroke. His medical treatment was inadequate and the medical expenses were such that it imposed a major financial burden which has still not been remedied, after more then a decade.
I am fortunate. I have reached that age in which I have access to Medicare. In addition to that my previous employer became my secondary provider with Medicare and provided me with an a program, I believe HSA. They make monthly contributions and I can claim that money for out of pocket health expenses. Last year I had about $2,500 worth of medical work in Thailand and was completely reimbursed. Then again I could have used those expenses as taxable deductions. Either way medical costs in Thailand are such, for the most part, can be an out of pocket expense.
As I've said earlier - health care is an individual choice relative to your own individual circumstances. Like playing chess - make the best move that fits your needs.