which markets is the question

See, I think a flat tax probably is more efficient money-wise (the article didn't show any evidence it). Just like a kidney market is efficient.

However in both cases something is lost. The efficiency comes at a price.

For kidney markets it would entail devaluating the body ("if kidneys cost $X, how much for the rest, sir?"). Quite a few people think it's worth it. They don't think bodies themselves are all that valuable enough.

For a flat tax, it would trade compassion/equitability for higher growth (more so than today, at least). It may be a trade society wants to do. Hard to tell. Either way, I think an economist stops being just an economist when they advocate for markets - it's like a bus driver arguing for more mass transort, or a nephrologist arguing for more kidney transplants. That's why so many economic theories are mere proxies for ethical, political ones.

chains and choice

They increase local variety, even as they reduce the differences from place to place. People who mostly stay put get to have experiences once available only to frequent travelers, and this loss of exclusivity is one reason why frequent travelers are the ones who complain.

Exactly. The average (choice) is better than the extremes.

addiction as an organizing principle

Increasingly, exercise can become the ‘organising principle’ in the persons life at the expense of non exercise activities - relationships, family, work etc.

An interesting notion. That addiction by reducing choice organizes a person's life. It's actually useful.

chocolate bonhomie

Must admit - chocolate is one of the most efficient presents - per dollar, a bonbon packs quite a bit of bonhomie (legal and OTC).