I'm going to travel in South America (Peru, Bolivia & Chile) for a month. Is travel health insurance necessary / a requirement?
I mean those kind of insurances for emergencies, so that if I recover in a local hospital I'm covered with the costs.
Absolutely yes. Medical emergencies are one of the few things you definitely need to be insured against, as they can bankrupt most people. Since most regular health insurance policies don't cover treatments abroad, you need extra insurance.
Mere mortals usually think that travel-insurance is a really really good idea.
But it is never "necessary" if not required as a condition of travel by some third party.
and / or
if this excitement, for you, exceeds
A personal experience:
On a visit to China I was bitten lightly by a friendly factory guard dog while playingh with it. (We were and remainded the best of friends).
I was introduced to the logical considerations of potential Rabies infection and its relative prevalence in China. I underwent a course of injections - 1st in China, two more a week apart as I subsequently travelled in Australia. Final one in NZ on my return home.
Total cost the better part of $1000.
Only on returning home did I find that my travel insurance was invalid! (Free Gold VISA travel insurance does NOT apply to travel with a business component).
Had the dog actually had Rabies or if it did have and the injections did not work then I could have died rather unpleasantly (insurance helps only a little) or needed very very substantial ongoing care. Rabies kills almost everyone who is actually affected so maybe not the very best example. Choose eg tetanus and try again.
Paid travel insurance would have cost me about 1/3 of the Rabies treatment costs.