You don't need any form of insurance until you need it (that's like a Yogi Berra ism). What about trip cancelation, trip interuption, lost baggage , and health emergency.
We recently found our Summit Alaska cruise was delayed by 3 days (out of 14). Insurance paid us $600 towards hotel bills in Vancouver.
I have collected twice on minor health issues that were not fully coverd by my medical insurance.
Insurance is a rather nominal charge relative to losing the whole cost of your vacation and is a drop in the bucket relative to potential medical costs including evacuation to a major medical facility. We just count it as part of the ticket price and don't even give a second thought to it.