The point of the conference is not the official conference itself, but the meetings that happen around the conference. This is not true of all conferences, but for the JPMHC, and many other major conferences, that is the entire point. It's just a way to get people all in one place at one time, so that there is an efficient gathering to do deals.

Funds pay thousands, often $10K+, per room at the nearby hotels, often spending hundreds of thousands to book over a dozen hotel rooms to use as makeshift conference rooms. The hotels often don't even allow people to sleep in the rooms, only to use them strictly as conference rooms.

All the real action happens in those hotel rooms, at private events, private receptions, etc.