Either system is a valid solution to the problem of fraudulent charges, both have their advantages and disadvantages.
The PIN requirement for usage must be a European thing.
It is. Over here a credit and a debit card work in significantly different ways. In the USA (and probably other countries too) a debit card is just a credit card that's more likely to get declined and gets billed slightly differently. Over here they are entirely different transaction systems as far as I can tell.
It might be an added benefit but in the end you do pay a couple percent on each purchase for that insurance.
I don't know what it's like in other European countries, but I have to enter my PIN code before a transaction can take place (except for very small transactions). So since overcharging or webshops charging my account cannot really happen without my explicit permission, I don't really see how that could happen?
On the other hand, a credit card will give you back 1-2% of that in the form of cash back or other rewards. So in effect you are paying to not use a credit card.
Also, if you pay the balance in full every month, you don't get charged interest.
If you're disciplined, then you'll use credit cards for every cashless purchase.