Sometimes, the immediate feedback can be a problem in itself. If you are typing as fast as somebody is speaking, the last thing you want to do is recognize a mistake and try to correct it. Doing so will just make you fall behind, which is worse than having a typo in the transcription. Since mistakes cannot be corrected until afterwards, it is better not to be distracted by them at all.

This differs quite a bit from programming, where a single character typo might not be noticeable in review, and should be watched for while typing.