This seems interesting because they did some research in the actual mechanism that could create a cause-effect relation. Still need to be repeated to justify legal changes but that's a good start.
Much better than these "correlation" studies that say nothing. Like the ones saying "people who doesn't drink any alcohol die sooner that people who drink a cup of wine each day", that's totally faulty for a lot of evident reasons. And until now most artificial sweeteners studies were like that "people who use artificial sweeteners tend to have more health issues", like with the drink is reasonable to assume and consider that people who do such dietary changes is more likely to already have an underlying health issue that they are trying to cope with and it's obviously more in risk that healthy people that doesn't feel the need to control their diet.
As I said this study seems a little more promising as they did research on the actual mechanisms on which the health issues may happen. I hope it gets repeated enough times and, if needed, the product would be banned or properly labeled.