When editing, one needs to convey to users when it's safe to close the app without a risk of data loss. You might want to tell users that connectivity is down and stuff can't sync right now, but "draft saved" also confers some psychological safety that everything is OK. That I don't need to wonder about the state of my editing. I can safely leave and return.
There are ways to make that flash more or less. There are even basic ways regular editors do this by visually including a star at the end of a filename. But it will still need to display somehow if it's an environment where you're not hitting ctrl+s manually.
Not having some indication is worse than it flashing.
If someone asked me that flashing question, I would also say they are annoying and would probably stop using the site, HOWEVER, I would not have considered this, or other similar status indicators related to my work, that toggle automatically to be part of the problem.