The only possible benefits I can see are saving time on tight connections, and avoiding speed walking/running so that you don't get sweaty...on a short connection.
Otherwise, I just go via the cafe before hitting MLL/PP lounge.
I suppose in that line of thinking, it would be good for a semi-tight connection if you want to go to the signature suite.

Assuming this reduces missed connections to J, I'd hazard a guess that this minimizes rebookings and empty J seats enough to be worth the $ to AC. Maybe.

Or it lets people feel snobbish and have to spend time around the common riff raff, which AC is more than willing to accommodate as long as bums are in J seats.