[Rendello]

Fwiw, the way Raymond re-implemented dictionaries made them more efficient (the algorithms are the same, but it's now much more cache friendly), and had the side effect of making them ordered. He and many others advocated for having the ordering guaranteed going forward.

[randomswede]

And now they're locked into an implementation that is order-preserving, even if an optimization tomorrow could eke out another 10%, if ordering was not guaranteed.