the current required coverage is 3 million baht for mandatory health insurance, the premium got higher as you age, getting to be very expensive after 65 or so and usually no cover for pre existing illness, but the greatest worry is that the required coverage could be raised again sometime in future.
if you put great sum of money as alternative, i don'T know if acceptable, the worry is that the money got depreciated over time against the USD or other currency
it does help to prevent criminals escaping from a host country, but i wonder the record is still clean for suspects not caught or went through court proceeding yet