It's a good idea.
You'd just need to make sure that you can load the card online and to make sure that the card works in the local Spanish cash machine. Some cards are specifically geared for overseas transactions but charges do vary. Remember that there will be exchange costs as well as, possibly, transaction charges. Some cards offer very competitive exchange rates.
It would be sensible to start with a small amount just to see if things go smoothly. You should also not post the PIN in the same envelope as the card.
You will be breaking the terms and conditions in so much as the card will be issued specifically for your use and it will be non-transferable.