What use is WiFi on a TV screen?

A relative of mine called, who was told "something" by Costco, that their
Visio TVs have WiFi and therefore she wouldn't need the "box" whatever
that is.

I don't have cable, nor even a TV, but I suspect that "box" is something
that was added when they switched from Analog to Digital (or maybe it's a
descrambler).

They said they have to pay the cable company for a second box (the first
one is free), so, it's not a modem (because you'd only need one modem).

Anyway, my basic question, for you, is "what use is WiFi in a TV"?

Note that I can easily see that bluetooth is useful, since you can then
use that TV with a keyboard; but what good is WiFi in a TV screen at home?