The Guest, from the same team, is a much more terifying and thrilling movie than this movie.
Now we know why this got a title change. They knew they had a subpar product on hand and original horror films sometimes struggle to do well unless they get good to excellent reviews. They slapped the title of Blair Witch as it was kinda similar to that, did some reshoots and boom in the hopes that the brand name will help it become a profitable venure.