Even when traveling between Schengen countries, medical expenses and travel delays can arise, so I consider https://www.globelink.co.uk/policy-options/spain-travel-insurance.html before leaving Spain. The European Health Card doesn't cover all situations and usually doesn't cover baggage or trip cancellation. A travel insurance policy can supplement basic medical coverage and cover other travel risks. Do you consider the European Health Card a full-fledged replacement for travel insurance?