strange code in ediff-hook.el

[Dan Nicolaescu]

Is this code in ediff-hook.el useful:

(if purify-flag
    () ; if dumping, autoloads are set up in loaddefs.el
  ;; if the user decides to load this file, set up autoloads
  ;; compare files and buffers
  (autoload 'ediff "ediff" "Compare two files." t)
 [....]

It's hard to see why... What am I missing? 

Incidentally all ediff*.el files have some strange require/featurep/load
code.  Is that stuff really needed?