In the days of linear tape editing, EDLs were used to save and restore the timecode
information for each edit performed on a computer-controlled editing system. Since
timecode editing systems were expensive, many editors would perform offline edits
with window dubs (low-quality copies of original footage with timecode visually
superimposed, or burned, directly onto the image) and then create an EDL by hand for
delivery to a computer-controlled editing system for the online edit.

You should export your sequence to an EDL when you are transferring it to an older,
tape-to-tape system, or a system that doesn’t recognize more recent interchange
formats (such as OMF, AAF, or the Final Cut Pro XML Interchange Format). Because EDLs
are relatively simple, they are still the lowest-common-denominator file format for
exchanging edit information between editing systems.