And neither it nor defrag will make webpages load faster (a regular clean will make non-cached pages load faster but regularly visted one may be perceived as loading "slower")
As far as drive wiper:
Freespace wipe willl fill the entire empty space of your harddrive with data (random letters in a textfile basically) and then delete that data. Effectively a user would not notice any difference in the computer after the procedure is finished, but, it makes recovery of any document, that was deleted prior to the WFS running, harder/uneconomical to perform.
Wipe entire drive makes it similarly difficult to recover from but is applied to the entire drive and cannot be run on a live Windows system (for the logical reason that one cannot erase one's own plane of existence while simultaneously existing there).