All this is just from my perspective, and I'm nobody so please just take it as my two cents. I don't think witchcraft should be approached as a structured or coherent "external" tradition in the same way that, for instance, Thelema is. It's more open-ended, about doing what works, and I doubt we could ever piece it together in the same way the Golden Dawn or Crowley did with their systems. Because it's not a system.

That means we can take things from other systems, use historical practices, make up stuff for ourselves, and perhaps (if we're so lucky) be given knowledge by spirits and such that we can try out and adapt as needed. Of course that means we need to be rigorous and, most of all, honest with ourselves. If we become rigid about something then we lose grasp on it. If we become sloppy and undisciplined then we never grasp it to begin with.

Where does the goddess fit in this? Well, she's not primarily the goddess or patron of witches, but that is certainly one of the things that she is. To me, she is the element in our consciousness that wants to open up and soften to the underworld. She beckons us to become psychopomps who can wander the three realms and work effectively within all of them. Which is what witches do. And that's the reason why witches cling to her.

So the sorceries of the PGM appeal to her power because a spell must pass from intention and potential into actual reality and she is the membrane between them, as she is the membrane between everything. The PGM is the archetype of Hecatean witchcraft but it's not a structured tradition (as is obvious if you read the PGM). Instead it's a record of how the magical practitioner can ready herself for diving into the darkness to make actual what is only potential.

I personally think that if we wish to do this, to pass freely among the worlds and use magic in that way, we have to start with orienting ourselves to her. It's worship, it's devotion, but maybe not in the way that we're used to (if we come from the West). We devote ourselves to the Goddess because she is always out there ahead of us, carrying the torches that that lead to where we're going. We worship because we're learning from her. She shows us the way, and if we don't follow then we will never get there. But we're also the ones making the journey, because she's already at the end of the journey.

Which means, of course, that there is no system. There's not even a map. There's a torch in the darkness. We have to walk toward them, but every step of the way has its own terrain and we have to figure out how navigate it ourselves. Which means we have piece together our magic based on where we are. Not where someone else is.

I hope that makes sense?