Using DATEADD instead of less than or equal to when testing against parameters

I’m newer to SQL and I’m playing around with some existing queries in my database in SSMS – something I’ve been coming across lately is this line:

WHERE DE.Modified >=@FromDate
AND DE.Modified < DATEADD(DAY,1,@ToDate)

Where FromDate and ToDate are given parameters. What I’m wondering is why one might write the second line instead of:

AND DE.Modified <=@ToDate

Is it a best practice in SQL to only use the less than operator and test against a date + 1, or are these the exact same?

EDIT:

FromDate and ToDate are declared as DATETIME:

DECLARE @FromDate DATETIME 
    ,   @ToDate DATETIME

Answer

You would write this to handle any time component on Modified.

In your version, anything that happens during the day of @ToDate would be missed.