I was always scared I would dry it out going hot & fast but reading this thread has me wanting to give it a try.
It's kind of the opposite in my opinion. It's easier to dry out low and slow, but there is a sweet spot somewhere between fast/slow and tender/tough. BBQ is basically purposely overcooking meat that is then saved by fat and collagen. Any meat fiber that is cooked to 200 degrees or so is going to be dry. Then the magic of collagen makes the meat itself seem moist even though it's just super tender not actually moist.
In the case of a brisket flat (which is what most people including me have trouble with), there is hardly any fat to render off. So the faster that you can cook that meat to tender, the more moisture it will retain. The trade-off when you cook it too fast though is sort of a roasty tasting brisket. Not enough smoke, and a quick cook. Also, during a high temp cook, sometimes I end up with a rubbery point. The flat may be perfect because it doesn't need to melt as much fat, but the point hasn't had enough time to cook properly.
When I cook hotter I typically need to cut off the point and let it go longer to make it melt in your mouth like a low and slow cook. If I wanted the best of both worlds I would cook a fast flat, and a slow point.
This picture is of last week's 5 hour choice brisket. This was literally just sliced in half right down the middle of the flat. I didn't press on it, brush on the juices, or in any other way modify it. As you can see, it was extremely juicy for an averagely marbled brisket. It also was decidedly roasty. I cooked it in my insulated cabinet, and am still working on how much wood to use. Not enough wood here, and probably a little quick. The point probed soft the same time as the flat, but was still pretty chewy. Just too quick for all that point fat to do its thing.