QWERTY is the standard US keyboard layout. (With close variants in other countries.) It was originally designed to avoid mechanical collisions of typewriter hammers.
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You don't have to carry your own keyboard everywhere, QWERTY is pretty popular.
Pro Default keyboard shortcuts
The keyboard shortcuts for most applications were designed with QWERTY in mind.
Pro Good for Vim users
Vim is most natural in QWERTY, since this is the layout it was designed on. Learning a good editor will help with your programming a lot more than learning a new layout.
Pro Easy access to important keys
Some of the most used keys in programming such as ; . / " | ' < > * are very easily accessible because they either have their own keys or are "shift options". People who grew up using alternative layouts, such as Belgian AZERTY, know from experience this shouldn't be taken for granted.
Con Not an easy to gain speed on QWERTY
Learning to touch type using traditional touch typing methods, you would not be as fast as others on Dvorak and you would be making quite a few mistakes.
The reasons that most of record holders have placing in typing speeds is because they do not use traditional typing methods.
Con Made for typewriters, not computers
It was created before computers got popular. This layout was created for typing machines, so as to prevent collision between character hammers from slowing down the typist.
Con Correct typographic letters and symbols not easily reachable
Con Very unintuitive