The advantage of this is that you can add US ratings such as instrument etc on to it whereas you can't with option 1.
You can add any US rating to a validated certificate.
IR, Seaplane, ME anything you like.
It will read "US test passed".
You can also add foreign ratings to a validated US PPL by going through the validation process again and having it added.
Example, this year July you apply for and get a US PPL SEP validation.
In two years time you add a Multi engine rating in JAA/EASA land.
You can now re-apply for a US validation with those ratings added.
Get a move on though, you are already late for July as this process can take up to 60 days.