Shading used to take a lot of time and mean several, sometimes many firings. There’s nothing wrong with this: why should beautiful effects be quick and easy to achieve?
But shading also used to be a worrying experience: “Has it worked?” you’d ask yourself – and then you’d have to wait for it to fire before you knew.
I think these techniques make shading more enjoyable than it used to be. And also more immediate: you can see quickly that it’s worked – and you can also make adjustments till you’re happy:
If you’re interested in shading, look here.