This is super cool, but I'd be cautious about the usefulness of this data set.
Both this data set and LibriSpeech are read speech, where the speaker was prompted with a transcription and asked to say it out loud. In practice it's very rare that you're trying to transcribe speech that's already been transcribed. Speech patterns for computer-directed speech (e.g. for voice activated user interfaces) or human-to-human speech (e.g. for meeting transcription) are quite different.
Both this data set and LibriSpeech are read speech, where the speaker was prompted with a transcription and asked to say it out loud. In practice it's very rare that you're trying to transcribe speech that's already been transcribed. Speech patterns for computer-directed speech (e.g. for voice activated user interfaces) or human-to-human speech (e.g. for meeting transcription) are quite different.