I always advise that everyone should have insurance. There are better choices outside of the cruise lines policies but even that is better then nothing.
Once you have a client (I've had a few) need an evac off a ship by helecopter and then need long term care and a private chartered flight with medical personel aboard to get back home for that care and have insurance pick up the tab for every penny (nearly $100K in total costs) you believe. This was not an elderly person for all those of you young and healthy who think its wasting your money. It was a 14 year old boy whose apendix ruptured. Other complications arose as the medical care outside of the good 'ol US was not up to par.
Long story short, the family avoided financial ruin by having the ins. The little guy is fine now.