Oh, it does matter. It can give a boost. People select the day of the week for this. But so does everyone else and their dog. So it matters a lot less than people think. And then comes the bad rng that decides to not index a game in time for such a release and people are sour.
Itch is a self publishing site. The only promotion people should rely upon is the promotion ouside of Itch. (I paraphrased the stance of Itch here, but pragmatically, that's what it boils down to.)