Actually, in this case, it wasn't for me(I use the devlog sometimes), I found myself browsing someone's project, and  it seemed utterly dead, I looked at the more info and could only see the release date(a few years ago), this person didn't use the devlogs I guess. And didn't use the community feature, so it seemed like the project was sort of abandoned? I asked them when was the last build made and it was just last week! I figured that this should have been something I could have seen there.

It could be any activity at all(changed the page's style, added screenshots, change the name of a file, etcc), it doesn't have to be just devlogs.