I have never purchase trip interruption insurance. Since I retired and went on Medicare, I am apt to consider buying insurance that includes medical, as Medicare does not cover one in a foreign country.
Recently, we went to Africa on safari which included three countries and remote locations. Getting medical of any sort would have been hard, quality care nearly impossible (the real risk, and uninsurable). We bought insurance for medical and for trip interruption (comprehensive policy had full coverage medical and transport). The medical insurance adds the dimension of providing coordination of resolving your issues (booking, reservations, coordinating with hospitals and specialty transportation). they have done it before, I have not.
We are going on a cruise soon to the Arctic (northern Europe). Getting good medical care will be easier, and closer and the ship is my transport. I will take the medical cost risk. Modest medical assistance is provided on board, and the ship will assist in coordinating relocation, if necessary.
Most countries will treat you free in an emergency and get you stabilized. Knowing the care quality available in nearby countries is a key in my mind. Medical care outside the USA is usually considerably cheaper.