with regards to the numbeo figures: these are pretty offset by the high price of Milk, Bread, Cheese, Apples, Wine - all of which are non-native foods and would have to be imported to Cambodia (and which wouldn't be part of an average diet there). In fact, most of the foods there are non-native - potatoes? No-one's eating these either.
Local food types (rice, noodles, veg, SE Asian fruits) are ridiculously cheap in Cambodia, though could still very well be expensive in comparison to the wages..
edit: reading further, I'm not sure they've sourced those figures well at all, they don't ring true. 0.43€ for a bottle of water? Come on, that's nowhere near the local price unless you're buying it at your western hotel