Why? It's only important to give the player a sense of the passage of time within the game itself. In a changelog it's meaningless. You have zero context in a changelog. Moreover, content per day varies greatly between developers. For some, literally nothing happens for multiple days. For others, the entire content update takes place within a single day, sometimes in less than a day.
As far as I'm concerned, render count and animation count is the most important data set to me as a player for a changelog, as it is a fairly reliable indicator of how much content is added. I literally do not bother with downloads unless they're at least 1k renders. This is the only dev I make an exception for, since he's usually close enough. Everyone else, I just wait for a second update before downloading. Of course, it's not completely accurate, as you can inflate render count with facial movements, same scene poses, etc. However, that uncertainty pretty much disappears as soon as you're familiar with the style of the developer. Bonus points for describing which character(s) were the main or minor focus of that content update.