In small doses it can seem harmless, but here's the thing. It provides an opening for bad things to happen, and the more you do it the more that opening widens.
A lot of stuff now is rather watered down, but when you get into the old shit, the dead languages and rituals.... it's not great. Do not mess with talking to the dead and whatever you do, do not fuck with ouija board's.
If you do, get help from an experienced legit, priest. Lot of demonic activity starts out as something ordinary going wrong that doesn't make sense and gradually gets worse and worse, before you actually start hearing and seeing overt stuff.
If your curious Id advice reading Diary of an Exorcist, it lines up nicely with what ive heard in person.
https://www.amazon.com/Diary-Americ...cphy=9012133&hvtargid=pla-1244663120302&psc=1