A sudden announcement like this from Twitch doesn't well indication for the gambling company. It is believed that Twitch may have banned this gambling sites due to some kind of restrictions by the government or others. Nowadays gambling has become a big industry. But I hope that such restrictions may be reduce in the near future. Besides, all these companies have to take alternative route for gambling promotion.
Only stake, duelbits and roobet? But, what about other gambling sites? Because I heard the ban is only selected but gambling streams are still there and will continue. I don't think the gambling sites that I mentioned are illegal but I believe all of them already have their own licenses.
The ban has also nothing to do with country restrictions because it was only a streaming service. Given that the gambling industry is growing, we can expect that more bans and restrictions like this are going to happen in the future because there are people who use gambling in a wrong way and there are concerned people or institutions that are taking an action to help combat the issue.