The Big Mac is so ubiquitous The Economist developed a price index for the burger as a way to measure purchasing power parity across economies.
McDonald’s changes its offerings to meet local demand. For instance there’s no beef in Mumbai McDonald’s but they do offer several different fry dips.
In Bangkok Ronald McDonald greets you, sawadee krap:
McDonald’s is quick and cheap. I’m not sure it’s the best thing that’s quick and cheap, but it’s also efficient in terms of not needing to invest in learning about options. So I do understand why people go in there when they travel.
United Airlines even served McDonald’s on Orlando flights years ago, modifying their galley carts to keep the cold items cold and the patties hot.
My reason to go to McDondald’s though has nothing to do with the food. I go there, I don’t eat there. That’s because you can count on reasonably clean and available restrooms.
If I’m out in Mumbai all day, not everywhere I go is going to have a restroom. Or toilet paper. Toilet paper is getting more common in China than it was when I first visited, especially in major cities. (Although it can be a good idea still to carry your own in some places.)
McDonald’s are easy places to walk in, relatively unnoticed, and use the restrooms.
Now in many parts of South Asia McDonalds delivers. But since they do not deliver clean restrooms I don’t really see the point.
I don’t find the McDonald’s restroom tip especially valuable in Europe, because of the prevalence of first world amenities you’ll find most everywhere you go. And yet on Las Ramblas in Barcelona, one of the most touristy of tourist areas, you have pretty much every fast food to choose from.
There’s plenty of Spanish food there, too. But if you’re going to eat tapas, try to do it somewhere other than Las Ramblas. The food will be better (not to mention less expensive, because of the rents).
Since there are clean restrooms all over Barcelona I cannot offer a justification for Western fast food. But I’m grateful that it’s popular in many of the places I travel where I couldn’t otherwise find a place to go.