Is there any need/benefit to migrating from my perfectly functional SmartThings v2 hub to Aeotec?
Not really 
Not currently, there may be in the future when Smartthings turns on the Matter and Bluetooth antennas in the V3 hub. I am hoping Smartthings will add a USB dongle to the V2 hubs to support this on the V2 hub.
I don’t see a USB dongle happening. But yeah, in the future there could be a good reason to migrate if Samsung turns on the Thread and/or Bluetooth radios in the Vs/Aeotec hub. Probably won’t know that until SDC, though.