Health insurance is something that many young healthy people don’t think about. And many digital nomads are young healthy people, though not all of them are. And if you are from most rich countries you may not think about health insurance as your country makes it pretty easy to just be treated if you have health care needs, without a need to have bought health insurance.
But when you are traveling outside your country health insurance is important. I am not very familiar with the details of how health coverage works for all the different countries so you will have to figure it out for your own country. It wouldn’t amaze me if European countries set up some kind of reciprocal care agreements but I have no idea if they do (they should if they don’t).
In the USA we know what a nightmare health insurance is. The ludicrously expensive USA health care plans generally don’t provide any coverage when you are outside the USA (even inside the USA, but not in your own state there are severe limitations). There are many wonderful things about the USA but the health care system is a nightmare and has been for decades.
If you are going to fly off and become a digital nomad one of the critical items to consider (though many don’t give it the attention it needs) is health insurance. It is true that in many countries you can pay out of your own pocket for health care that would bankrupt you if you used the USA health care system and tried to pay out of your own pocket (tens of thousands of people go bankrupt in the USA due to health costs).
If you use good personal financial planning practices you should have at least 6 months of expenses in an emergency fund (and I would strongly suggest at least a year for any digital nomads). That emergency fund should be able to pay for routine medical visits in many countries (Malaysia, Thailand, India, Indonesia, Vietnam, Singapore… – I would imagine this is true in most countries, but certainly not the USA.) without a need for health insurance.