Have you ever played video games it’s not as weird as you think it’s the same thing using a headset playing games your talking to your friend but also the monitor
The game they are playing is freebet blackjack where doubling down on a 9-11 and splitting 2-9 and aces is on the house so it's "free" so house needs their edge so there is a special rule where dealer 22 pushes on anything that's not blackjack