To most secular people it sounds strange to refer to Satan as a real, active being. As you point out, he has succeeded in convincing people that he's not real. That at worst he's some cartoonish person with a red costume and pitchfork. So if you don't believe in the reality of Satan, there's not much reason to turn to Christ for protection.
Imagine how the covens and Satan feel when we ridicule their power by sending kids out in funny costumes to get candy.
How would Satan feel if you used Halloween to invite kids to church? What if you handed out invitations with the candy? Would he be pleased?
Or Satan be more pleased if you hid in your house and hoped it would go away?
Yes. It’s Satan’s greatest accomplishment, fooling people into believing he’s not there.