The lack of a traditional Wi-Fi range
Traditional Wi-Fi networks provide Internet access to all your smart home devices, and the distance between the router and the device determines the strength of the signal used to operate the devices. The average signal range of Wi-Fi is between 30 and 100 metres. With thick walls, even 5 metres can be difficult to reach, and reinforced concrete is often a challenge. Is your house built like this? If so, your devices may not work as well.
The advantage of meshing technique
ZigBee is a meshing technology. This means that every ZigBee product uses some power (such as a lamp or sensor) to repeat signals from other devices in the ZigBee network. If you have more than one ZigBee product in the house, you will improve the effective range of the signal. This means that you can now reach the devices just outside your old signal.