What are the advantages of WiFi signal jammers? Where is it mainly used?

I found that WiFi signal jammers are installed in many places, what are their main advantages?

Topsignaljammer  2022.3

It is necessary to use a wifi signal jammer, on the one hand to ensure the security of the network, on the other hand, it can also control the time children use the Internet, do not indulge in the virtual world, it will cause serious damage to their body and mind. In addition, the radiation of the wifi transmitter will It affects people's health and should not be used for a long time. You can open the wifi signal blocker to block the wifi signal.