Most of the use cases we need to handle deal with a simple, straight up Date. Like the End of Financial year. For this, we don't care about the TZ. EOF is universal, doesn't matter whether you enter it in Fiji and you read it from Canada, it is always the same and you don't want to associate it with the TZ. Another example would be date of birth. According to the Fijian time, technically I might have been born one day earlier, but this is irrelevant and for the purpose of storing and matching the DOB.
On the other hand, the DueDate, yes indeed, might be TimeZone related. For the Fijian operator a process is Due on 10/10 at 07:00 - let's say; same process for the Canadian should be due on 09/10 at 17:00.
I am surprised that Progress didn't catch this distinction so far and leaves it to the devs to handle the TZ conversion of what should be "TZ agnostic Date/DateTimes.