These streamers are actually streaming newest game as soon as they especially those that are hype so they can attract as much viewers as possible. Theses kinds of stream are kinda an in-depth review so we the viewers will know if we will want or be attracted to that game.
Anyways, Upon checking "Slot Category" on stream, my first thought is that gambling activities on Twitch are not allowed but to my surprise, various gambling games are actually being played and stream there. Also, I was able to find Stake being streamed on the top of Slot category and it has a lot viewers compared to other gambling games.
Well, we may find many streamers who use online media to promote something live or recorded. This has become a new trend among streamers, so many are trying to follow it. In addition, many streamers also share their experiences about promoting something, not just sharing an evaluation video about a product.
The online gambling business that has been developing for the past few years has attracted streamers to join and participate in promoting it because it can increase their income and, of course, the streamers can get even more subscribers.
The videos used by streamers as a content will always come from their live streaming. I don't know why but once they were doing live streaming and they were getting very very big win. They were using their video to attract people to join through their refferal. The rate from their video was so smalll compared with what they have gotten from people joined through their refferal.
Maybe they want to show their subscribers how they can win the game so they decide to have a live stream on their channel. That can attract more people to subscribe because they will think that the streamer might share something with them, whether it's a tip, trick, or even a gift. Those streamers will also share the link to join and of course, if people join under them, those streamers will earn extra income.