Of course one could do this but this is about comfort and ease of use for the learner. Adding a button or icon isn't a best practice for those who use devices such as screen readers, eye gazers et. al.
The idea is to make the end user with disabilities comfortable and the access easier. I would think a downloadable transcript would be a natural function for the player since the edition of the transcript within the player.
Interactive transcripts are searchable and with the ability to find specific points in a video
They are essential for those who are deaf, or have difficulty seeing (or interpreting) visual information or those with multiple disabilities like deaf-blindness. However, I hope Articulate might consider getting rid of the time stamp (on the transcript) but keep the highlighting as the timestamp is distracting particularly for those who use a screen reader.