'but why does this have to be coded two times?
It doesn't, unless the developer wants it to do that. In the first call you are passing the system date as noted. In the second, you're passing a hard coded date which doesn't need a conversion function if you write it as #08/01/2021#
EDIT
BTW - isn't the first test in the IIF function testing if Sunday = Saturday? That will never be true.
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.