Only with newly created files really.
I mean in this day and age, drives aren`t basically slow even with minor fragmenting.
You can go alot deeper with the likes of PerfectDisk?? (I think it`s called), where it`ll put highly used files at the quickest reading area of the drive and things like that...
Dunno if it`s exactly worth it today tho.
I will say this tho - when I get my act together and have all my legit tools arranged on a data drive for every install I do for myself, this sort of defragger might make it`s way on there. No an essential tool for me tho.