Supposedly the venue holds roughly the same number of people. The benefit for Apple is that their engineers don't need a full day away to come to the conference so they'll be able to send more engineers.
The number of engineers is dwarfed by the number of attendees so not really. And they can rotate more engineers e.g. have people there for half a day, it's not wasted when it's a 5mn trip from HQ versus an hour drive to SF.
