I first found out about day clocks when I was researching a way for my Mom to feel more comfortable knowing what day it was. The bonus of having a day clock in my house was also that I, as her primary caregiver, also knew what day it was. There were literally days on end where I had no clue if it was Monday, Tuesday, etc.
I prefer the digital day clocks as, sometimes, those with Alzheimer's or dementia lose the ability to tell time on a regular clock but reading continues as normal. A digital day clock gives easily shows the time in digital format - this is a much easier clock to read for senior citizens as there's no clock hands to try and figure out.