Good data (and program) structures are definitely quite important. Well chosen structures make implementation much easier (and likewise bad structure makes things needlessly difficult).
Also, the film editing example is also an example of a piece table, which makes cutting very simple. Cutting out a section is just a node insertion + update the end of the original node ({0-3} -> {0-1}, {2-3}).
The example implemented in Mithril.js, for comparison.