Asynchronous compute is about using unavoidable GPU down-time. No matter how complex the graphics, there are spells where the rendering has a lull and the GPU is twiddling its thumbs. Async compute fills those holes with work. There's definitely a good couple of hundred GFLOPS available there for a lot of titles, although that may be purposed towards compute-based graphics as much as fancy AI or physics.
Correct, but I'd be a little stressed about thermals then, have the consoles been made so that the GPU&CPU run close to 100% a fair amount of time ?
Last gen proved they don't always make the best decisions when it comes to cooling...