A lot of people land here trying to sort out the difference, so here's a plain breakdown of what actually cools you at night and where each option fits. A fan or AC cools the air in the room, not the bed. That helps by evaporating sweat off your skin, but it doesn't pull heat out of the mattress, which is where a lot of us trap it.
Cooling sheets and foams feel cool for the first minute, then warm up to body temp and stay there. Active cooling works differently.
With a Chilipad, water runs through a thin pad under your cover, and the unit heats or cools that water to hold a set temperature all night. So instead of cooling the room and hoping, you're pulling heat directly off the surface you sleep on. Dual zone means each side can run at its own temperature, which is the fix if you and your partner never agree. Honest tradeoffs: you need space for a control unit, and it's a bigger spend than sheets.
Worth it if you sleep hot, deal with night sweats, or share a bed with someone on a different thermostat.
Happy to answer questions.