Because if everything else is the same or extremely similar, why would you pay more for something slightly slower.
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Except that's not what the article is about, it's not about the apps on Windows/iOS/Android. It's about Android manufactures (hence the title "They're Almost All Dirty: The State of Cheating in Android Benchmarks) artificially increasing benchmarks (and most importantly ones that are designed to mimic real world usage, not just "how fast can this chip theoretically go") which ends up misleading a consumer. So I'd make the same point again.
Who would willingly pay for something that's extremely similar to other options (battery life/apps/camera etc) for something that's slower? Clearly there's value in cheating, otherwise it wouldn't be worth the effort.