Cannot speak for anyone but myself but I realized I'm a very religious person in that I get alot out of doing a spiritual ritual if you will. Its cathartic, fun, creative, and I notice tangible effects in my being. Aided me in processing trauma, developing emotional intelligence, helping to change the habits in my life, helped me in my workouts, and with overall confidence.

None of the various forms of christianity did it for me, family on various sides are in various sects of it so got to experience alot. I studied comparative religion in college so read a lot of holy texts and some elements resonated with me, Daoism in particular. A friend is Wicca so she lent me some books that were enjoyable but still it right, eventually found a group that practices a luciferian spirituality in that we share meditation techniques, ritual notes, etc. With the shared goal of being our best possible self in every moment and the shared pursuit of self enlightenment without subservience to a deity. To me astrology, tarot, are means of divination. There are lots more, but all share the same thing which is tapping into the subconcious by using material tools.

My guess for western people into this is that they have become disillusioned with many of the religious pathways for tapping into ones spiritual being and as such seek alternative ways to do so. Unfortunately, as another mentioned, these circles are filled with grifters who take advantage of that to profiteer.