I've recently been experimenting with this, but it seems like stress itself either helps or harms me. Sometimes it makes me fluent and other times it just makes things worse, but the breathing helps with control, and I think that's important. If stress helps you but maybe you're too stressed, the breathing exercises can help dial it back (for example), I feel control or the sense of is very helpful, and that's because of the breathing and having control of it -- something to think about