The world is a beautiful place, go see it!
If you are going overseas you want an insurance product that will cover you in case you get sick or injured in a foreign country.
The majority of health insurance and Medicare plans stop coverage at the US border. Not only will these give you coverage in other countries, but they will also secure a way back to the US if you miss your transportation due to medical reasons.
Other uses are missionary work and college abroad. Also, there is a growing list of countries that will not let you in without proof of insurance coverage.