I understand that regular Medicare does NOT cover out of the US. However, I have a Medicare Advantage plan that covers $25,000 for medical events overseas. I have chosen to purchase an additional travel medical policy because I want to be protected for more.
A little perspective seems to be in order here. A few years back, one of my wife's coworkers went to Mexico for a winter holiday. In a night of questionable judgement, she fell off a stage at a nightclub, and awoke the next morning in a hospital. After treatment that amounted to a concussion watch and detox, she was released from the hospital the next day with a bill for US$42,000 from the hospital. My reaction upon hearing this story was "Gee, why wasn't it $42,000,000?".
Last year, I came upon an American pilgrim who suffered a medical event on the trail early on. He was attended to, to his good fortune, by a pair of student paramedics who happened to be walking Camino at the same time. He was transported to hospital in Pamplona. His treatment involved some tests, pokes, prods, meds, and rehydration. He was released from hospital the next morning (and completed his camino BTW), and presented with a bill for 450 euros.
The public Spanish medical system does not engage in the same peak pricing policy for emergency treatments that some other jurisdictions do. It's easy to imagine a serious problem that would burn through a $25,000 insurance policy in Spain, but it would need to be quite serious. In other jurisdictions, it hard to imagine anything beyond a sore throat that would not quickly exceed $25,000. Medical treatment is a lot cheaper in Spain than most Americans expect.
By all means, buy medical insurance! But also understand that the total risk you are insuring against is quite possibly smaller than you think it is.