HVAC.com recently had a great blog about why NOT to use so-called Smart-Vents.  Read the whole article here: https://www.hvac.com/blog/smart-vents-vs-zoning-zoning-methods-best

It boils down to a couple of key factors:

1. You don't gain anything "smart" from these systems.
   - If you want a "smart" system, simply use a standard zoning system and add a smart thermostat like ecobee or nest
2. Closing the register to create zoning doesn't work as well as a damper
   - HVAC systems are not designed to handle the air pressure increase when registers are closed without a bypass or some other pressure relief.  This can cause damage to the equipment or at a minimum not create the desired effect.
3. The maintenance and cost is much higher
   - Battery operated vents means replacing batteries, not to mention the initial cost of many register vents that would have to be installed.  Instead of 1 damper per zone you might have 4 or 5 or even more of these so-called smart vents.

If you want a "smart" zoning system, choose SmartZone and use any WiFi connected thermostat for each zone.