If something has to be done on a certain day, I’ll put it on my calendar, whether that’s a task or a meeting.
Tasks are usually left as “all day events” unless they have to be done at a specific time.
I also tend to put my "Meetings With Other People” on a specific calendar, so I can always see just those things if I want to.
For example, I recently signed up for a ‘free trial’ that expires on September 24th. I created an all-day event for September 23rd that says “Cancel X Before Tomorrow”.
I have another one for the first Monday in October that reminds me to start planning for All Saints’ Day, which is the beginning of November.
I have one for September 7th that says “Check in with Officers” of an organization that is meeting on September 14th after taking the summer off. I don’t have to do that at a specific time on the 7th, but I want to do it some time that day.
On the afternoon of the 6th, when I’m looking at my calendar for the 7th, I’ll pick a time to actually do it, based on what I have scheduled for the 7th. Or I might write the email on the 6th and set it to send on the morning of the 7th.
When time blocking a particular day, I think it makes sense to schedule specific times for tasks. The key is to make sure that you can always easily tell your "Meetings With Other People” from everything else. To me, that’s not really difficult to do on a day-to-day basis.
So, while I wouldn’t just put “Reminders” on my calendar, but I would put tasks on my calendars. However, I tend to do that either the day before (preferably) or the morning of (if necessary).
Otherwise, I find that an “all day event” is a good ‘placeholder’ for things that have to be done (or that I very much want to do) on a specific day.