That makes sense, as you're using it with the A/C on, so you're blowing cooler air around, perhaps to where you want. But it's not going to help that much when it hits 25+ in the room and the A/C is off.
One thing I do want to do though is have a return right in my crawlspace, with louvers. Either automated or manual, then add louvers to the other returns. In summer I would just grab the air from the crawlspace which is the lowest part of the house. I would need to add louver/grille to the basement door though if I do that. This would make it so I can move cooler downstairs air back upstairs via the hvac system. It would probably help for a bit without needing the A/C. Once that's not enough then I'd turn on the A/C.
Another thing I want to eventually do is add an outside air return with heavy duty insulated damper. Would also have an ceiling damper/vent that opens up to let the air escape through the attic. This would basically bring the house temp down to whatever it is outside. Then they would close and the A/C compressor would kick on.
Definitely some things you can do by simply moving air to help conserve energy, but at some point you still need to just turn on the A/C if you don't want to be all sweaty in your house.