Tough question. I think you're going to hear a bunch of different opinions and at the end just be back at the same place, needing to make the decision for yourself, but for what it's worth here my situation.

I'm currently cycling from Washington State to Argentina. I bought travel insurance and have not used it once. However I will probably continue to pay for it. I cycled with a Dutch guy who had done most of the Alaska-Argentina trip five years ago. He made it to Colombia where he got hit by a truck. He spent seven days in a coma in a Colombian hospital where they opened his skull to relieve the pressure on his brain. I'm pretty sure he was glad to have insurance.