I know there are some out there who legitimately believe in the witchcraft they're performing, spells they cast, crystals, etc., but for me, I do practice wicca, but it's less about thinking that I'm having a physical effect on the world and more of a way to almost meditate and for sure a way to connect to my spiritual side.
Even though I know that me performing a ritual to bring a friend some good luck or something won't actually do anything in the real world, it puts me in a space where I can reflect on my friend and what they mean to me, for example.
It certainly can be a bit silly, but many of us practice because we like the state of being and state of mind it can put us into, vs truly believing we're performing magic.
I just saw a flyer stuck to a light post yesterday for a Witches Festival in my area next week. I took down the information and I'm planning on going! I mean why not? It seems like a fun and silly way to spend the evening and probably meet some wacky people that I thoroughly enjoy being around.