Originally Posted by
LondonElite
Because you'll have to clear immigration, which you wouldn't have to do otherwise.
You may not be aware but the transit desk (USA>INT'L) has been relocated within Terminal #1. No longer have to walk to the end of the pier via moving sidewalk and back track. It is a quick u-turn at the top of the pier and no more than a 5 minute procedure - infinitely much easier than JFK given the scope of DL's operations there.