On various visits to sistaur I'd see a book or two about Pagan or Wiccan topics and I'd look through them. These were clearly not just so much New Age nonsense (newage, as I've heard it put). I recognized the topic. It was largely visualisation and autosuggestion, a sort of self-hypnosis-light. It was just presented in a manner that might be more acceptable to some than the more, I suppose, clinical manner that I am more familiar with and generally prefer.
Various aspects can be taken as either forms of suggestion ("You don't do a spell to change the world, you do it change yourself.") or as means of extracting information from the un- or sub- conscious mind (divination - "Tea leaves don't know anything." as Terry Pratchett's Discworld witches say.) The one that I had the most trouble with was astrology. The best I can make of that is that, despite the cautions not to rely on the astrologer for too much, is that it seems to be using the astrologer as a therapist and the stars and planets as an excuse to see the therapist.
There is a lot of hokum, of course, but then consider what televangelists and "faith healers" do and it's hardly unusual. Not good, but not at all unusual. One thing I heard this past weekend was that someone had made a list of the things some particular item was good for and it went on and on and on... I joked about adding "...whiter teeth and fresher breath!" at the end. Evidently there were a few folks thinking that or close to it.
The gateway thing? A friend of sistaur had given her a pentacle necklace that she no longer felt any use or need for. She had found a different faith, Christianity. So evidently for her, Wicca was a gateway spirituality.