First I came to Thailand in 2016. I`ve chosen a car in with navigation and of course insurance. Because you can set on the map where you need to get and in any moment you can also control your location.
I agree that if you visit foreign country by rented car, you don`t know driver habits.
But for what I had traveled to Thailand? To acquaint with their nature, mentality, habits. The best way to see that all is to rent a car and drive wherever and stop whenever you want.