Dvorak does have some cons, but I'm not sure yours are really the most relevant.
1) Most OSs allow you to switch layouts with a hotkey like left and right Alt, right Alt+Ctrl, etc. (ubuntu and osx at least)
2) Typing on internet cafes, is not really the norm, and is something most people just a small amount of time in long periods to be really relevant. Its like having to go to an internet cafe in france (where some keys are misplaced), assuming you totally forgot qwerty.
3) On my mac, all shortcuts are where they should be, following dvorak layout and not qwerty. so close window (Cmd-W) is cmd-w in dvorak (which is relative to pressing cmd-.)