I've been seeing my neighbor's Vizio TV with it's own WiFi network, it's an open network labeled "VIZIOCastDisplay5742". Why do TVs have WiFi networks they emit? I thought TVs, like other smart devices, connect to your home network...

Now I'm seeing my other neighbor's TV showing up as "Cast TV7262.e002". Like the Vizio TV, it's an open network.

Do these networks enable external devices, like computers and phones to copy their displays to the TV?

I know some printers have WiFi networks they emit, to enable them to print from other devices over WiFi. LOL but if TVs have the same thing why are their networks open? I just tried connecting to one of them but am not sure if my phone's display started showing up on my neighbor's TV or what.