I would also point out we sometimes sync more the once a week, early sync + regular sync or cherry-picking a fix making the specific day less important than the week of the last sync. We usually lock old sync threads once they are no longer the latest.
Date stamp formats are also not universal. US uses MM-DD-YYYY this confuses a lot of people as most the world uses DD-MM-YYYY but there is also YYYY-MM-DD. Week numbers are just all round better.
Plasma users can also enable showing week numbers in the calendar.