Why strangers, and not just friends
Playing your friends runs out. There are only so many of them, they are only free at certain hours, and after the tenth game you both know exactly how the other one opens. The reason people queue on chess sites at all is that a stranger is the only reliable supply of a real game at eleven at night.
What the big sites take away in exchange is the person. You get a username and a clock, and the human being on the other side of the board might as well be a script. Meeting a stranger on camera puts back the part that made chess in a park or a cafe worth leaving the house for: you find out who you are playing while you play them.
What stops this going the way random video usually goes
Random video chat has a deserved reputation, and it comes from a specific design: no accounts, no consequences, and a next button that makes every encounter disposable. Somebody who behaves badly is anonymous and gone in a second, and the people who are left learn to expect it.
None of that is true here. Every player has an account with an email behind it, the site is for adults aged 18 and over, and the person you meet is not disposable: you can report them, and a report attaches a still frame of their camera to a queue a human being reads. Blocking is permanent and symmetric, and it follows the account rather than the name on it.
The camera rule does the rest of the work. Playing with the camera off is a breach of the guidelines here, not a preference, because a blank tile is how somebody behaves badly without being seen doing it. Turn it off for a moment when you need to, and turn it back on.
If you would rather not be on camera
There is a middle setting, and it is the one most shy players end up on. Blur keeps your camera publishing so the other person is still playing a human being across a board, and softens the picture so your room and your face are your own. It is one tap, it survives between games, and nobody is told you switched it on.
What does not work is joining and staying dark. A game against a black rectangle is the thing everybody came here to get away from, and the person matched with you usually leaves rather than finish it.
Meeting somebody versus adding them
Most games end and that is that: you say good game, and you both go back to the queue. That is the normal shape of it and nothing about the site pushes you to do more.
Occasionally you meet somebody you actually want to play again. You can send a friend request from the game, and after that you can challenge them directly with a link instead of hoping the queue puts you together. Some of the regulars here met in exactly that way, which is the part of a chess club that online chess had quietly deleted.