Help me make sense of some of these car rental questions

We will be renting a car for four days in Athens (driving to Naplio, etc). Our past car rental experiences have been through AutoEurope and we took the Basic Insurance and used our Visa cards CDW - but we never actually had to use it as we've been lucky enough never to have any damage.

In researching this rental I came across a thread here (which I can no longer find) stating that if you put in US as your country of residence you get a higher price than if you put in a European country. And this is exactly what happens. I called AutoEurope and the guy couldn't really tell me why that is, he thought it might be taxes. That makes no sense. My hotel rooms or meals are not more expensive because I'm from the US as opposed to France or Spain so why should a car rental? Has anyone else noticed this? Does anyone know what happens if you put in some other country as your residence (doesn't sound like a good idea but I was just wondering)?

Second question - with both AutoEurope and EconomyCar Rentals.com in the small print under their "inclusive" insurance, they say they don't cover things like tires, windows, mirrors. AutoEurope's even says it doesn't cover damage occurred while parking or in a parking lot. This makes taking the "inclusive" insurance sound like a terrible idea, it seems most common damage is things like broken mirrors or windows - or certainly damage while parking. Yet I know many on this board swear by taking the inclusive insurance. Am I missing something?