People using Word in this manner typically create a new filename only occasionally, not every single time they save. Browsers, on the other hand, will create a

People using Word in this manner typically create a new filename only occasionally, not every single time they save. Browsers, on the other hand, will create a new filename every single time a download is initiated. That makes downloads impractical to use as a web app’s sole persistence mechanism; a few smaller web apps do so anyway but it’s rare. And if they’re not the sole persistence mechanism, if downloads are just an export option separate from a ‘normal’ save, like you see in most web apps, then the 99.9% of users who don’t constantly export all their documents will have to deal with the consequences of the normal persistence mechanism. That is probably cloud storage, with associated centralization, privacy, and cost concerns, though it could also be browser-local temporary storage (cookies / localStorage / IndexedDB / origin-private file system), with reliability and portability concerns.