Going to predict a lot of big cities appear in responses here.
agree.
i.e. your local purchasing power is multiples the destination you're travelling to
correct - if you are earning USD or Euro, even better in BTC, generally you are fine traveling to many countries - I once lived in Ho Chi Minh, Vietnam and realized how much money I've save from living there.
most cities are pretty miserable to experience as a tourist. They're designed for living in and for locals.
it depends on what kind of tourists you are and what you are traveling for, short term is usually fine, but long term is definitely miserable because you would get to see way better options in the same country! and I think most big cities are actually designed for people that focus on making money ( not necessary for locals, many big cities trying to attract more foreigners than locals ) not really for living.