Personally, I'm a spiritualist and not religious but it's good to know that the Church of Satan and the Satanic Temple are two different things, I think. Or does it matter? I see what you mean regarding tax exemptions and validity pertaining too. From a strictly religious perspective if they are using  written word (The Book of Satan) and are organized with a body of people involved in the organization than I suppose it's undeniably a religion even if formally not recognized. 
According to Christian belief Satan is the master of deception. I believe Judaism gives a more complete history in my opinion which is humble in all regards.