I used to have Nests in my house, but for various reasons I eventually swapped out for Ecobees and moved the Nests to our vacation place. The main motivation was that the Ecobee let us add additional sensors in the bedrooms and smart vents that open/close in coordination, depending on individual room temperatures. I liked the Airwave option - Ecobee has something similar called Fan Dissipation.
You can see the hourly circulation cooling down the aggregated upstairs temperature, without any compressor/cooling needed, in this graph from Ecobee’s web app (the little drops in the white line)
. The white bar at the top shows that the compressor/cooling is only needed when my wife manually turned down the thermostat.