Except that it will get it wrong infrequently but often enough that you should really proof-read the result properly. All of which you end up taking more time than if you wrote proper if the first case.
No, it takes less time. This is the same kind of take as the teacher's "writing a cheat sheet is so much effort that you might as well spend it to learn the material". Lol, no it takes less time, that's why people do it.