Legal Framework
In most countries you are allowed to take photographs from public areas, and what Google is doing is no different.
In UKia, we're having difficulty taking pictures and not getting arrested without some over enthusiastic plod claiming we might be a terrorist, so I don't
As someone else has said, if you're house hunting, it means you can see real pictures of a property and its surroundings, instead of the guff the estate agents hands out. Its also good for navigation, as you can see the place you're looking for in the context of its surroundings.
In short, it's perfectly legal and has many uses, so why are people moaning about it?