Passing DateDiff Rather Than Actual Dates As Parameters

I've gotten sort of fed up with dealing with regional date settings on
the client side and am considering the following scheme - just
wondering if anyone has a negative view of it or not:

Instead of

@StartDate datetime,
@EndDate datetime

Use:

@StartDaysDiff int,
@EndDaysDiff int


In the front end app take the desired date and do a DATEDIFF with the
current date, then pass the date diff as a parameter as an integer
rather than deal with the dates at all.

Then...

DECLARE @TodayDate datetime, @StartDate datetime, @EndDate datetime

SELECT @TodayDate = GETDATE()
SELECT @StartDate = DATEDIFF(DAY,@StartDaysDiff,@TodayDate)
SELECT @EndDate = DATEDIFF(DAY,@EndDaysDiff,@TodayDate)

SELECT
a.Something
FROM
dbo.Appointments a
WHERE
a.AppointmentDate BETWEEN @StartDate and @EndDate

Just wondering ...

Thanks,
lq