The first is what is blocked and why. A due date can tell you something is late. It cannot tell you that it is late because the client has not signed, and it certainly cannot tell you that you flagged this a fortnight ago. So the reasons live in your notes app, your inbox and your memory, and the three of them disagree.
The second is what got done. On the Friday of every reporting cycle you go looking for evidence of a month you definitely lived through, and Apple Reminders has thrown away every task you ticked. You end up reconstructing the month from your calendar, which is a record of meetings rather than of work.