The EHIC form entitles you to FREE health cover if you are in a country in the EU.
If you dont have the EHIC form then there may be a delay in you getting health cover if you have an accident, and you may have to pay for your health cover while over there and claim it back from the insurnace when you get home.
After all, if you have a minor health problem it is better to get it sorted for free with your EHIC form than to go to all the bother of dealing with the insurance company when you get back.