In large-scale documentary projects it's really useful to keep the original TC visible for reference in all stages of editing (from rough cut to final cut). When you make a rough cut using the text-based editing tool a new time code is created (from 00:00:00), but it would be really useful to preserve the original TC as well. A lot of producers print out transcripts on paper or create their own documents outside the editing room. So keeping the original TC visible in text-based editing could be really valuable.