[Someone]

One aspect where .doc beats .html is in the ability to rapidly write small changes to disk. Open a document, edit a few characters near the start, and save. .html would have to write the full document out to disk; .doc could write less than a kilobyte.

That was extremely useful in a time where programs crashed all the time, necessitating frequent saving, and floppy disks, with write speeds in the order of 50 kilobyte per second, were the main storage medium.

This feature lives on in Word as “fast saving”, but can be disabled.