Personal experience why medical insurance is a must.
There is Mrs A I know. She looked quite healthy. One fine day, during one of the regular health checkups, she was diagnosed with Cancer of stage 3C. Result was "surgery + chemotherapy", which led to huge medical bills. Given Mrs A was a house wife through out and Mr A is a retired man, this bill would have been sufficient to take away all the savings of this elderly couple.
The couple had a son, who had medical insurance through the corporation he worked for. Parents were also included in this. Son filed the claim of the surgery to insurance company and after one month and two days, they got back their claimed money (minus some deductions of course).
Here anyone can be "A". Emergencies are Indian, they give no prior notice before arriving. So, please beware of them and prepare in advance. Please insure your family properly.