Give the size of most ODT files and the power of current computers, incremental updates are completely irrelevant. Regenerating the entire file takes a blink.

Give the size of most ODT files and the power of current computers, incremental updates are completely irrelevant. Regenerating the entire file takes a blink. But the current format benefit from the XML ecosystem (validation, transformation, namespacing, nesting, semantic markup) that is very handy for a document. Plus, being text based is a very good selling point if you want your format to last: event in 30 years if you don't have the spec, you can peak in the zip and see what's up.