How does Smart Connect know which band is best for each device?

Smart Connect relies on an advanced algorithm that not only automatically determines which band is best for each device,but also constantly monitors the overall status of each device to determine if and when a particular device would benefit from being automatically reassigned to a different band.

==================

I highlighted the last sentence. 'reassigned' is the key here. That is called different names but 'load leveling' or 'load balancing' is what it is. Keeping the 'usage' on each band equal, which usually means the number of devices. Worse (to me) is that it can in doing so, slow down performance for some devices. Putting a fast device on a slow band, or a slow device on a fast band which can cause performance issues for the fast band.

As for " Main reason for wanting to do this is for security that way less secured devices like IoT for example can't communicate to other devices. ", well, you can't isolate SSID's on the LAN from talking to each out. Yes, if you have both the Guest and Normal SSID's in use, you can do that between Guest devices and the normal LAN devices, but again, just because a device is on a LAN doesn't mean they can 'access' other devices. Most devices don't allow that or have no method to do it. For instance, if this were true, then a printer on the 2.4Ghz SSID wouldn't be able to print from a device on either 5Ghz SSID.

The 'Smart Connect' is for someone who either doesn't want to manage the SSID bands or doesn't know how to do it. From a true performance and knowledge of the LAN and its devices, you are always better off managing the LAN SSID's.