Having moved between developing and developed countries recently, I was reminded of what GDP in PPP misses. It's even cruder than how inflation is measured through CPI or RPI. In one country it might be cheaper to get services that depend on a lot of labour, like restaurant meals, cleaning and tailoring, but in another country you can walk or take public transport to the restaurant or tailor without the fear of being the victim of a crime. You can buy ketchup for cheaper, but it is not necessarily as safe or hygienic, it won't have seals under the cap in the store, you won't have as many options to choose from, etc. I think in a globalised world and especially when you look at commodidity prices, PPP is good to measure if people have 'enough' to live on in a particular location but for comparison between countries it's pretty meaningless.