When you are travelling in Spain it is a good idea to use a VPN.
When you are using a public wifi system such as you will find in hotels, cafés and restaurants it is fairy easy to intercept the traffic from your smartphone of laptop. This could be very important when you are sending sensitive data such as credit card details.
Another advantage is if you use a TV streaming service and you wish to appear to be at home.
Some companies such as NORD VPN