People say that it wasn't as scary as the first 2, but it's scary in a sense that it goes way deeper into Lorraine's superpowers because not just she have a sense of what happened from when the violence occurred, but she can do those actions herself to see how the demonic possessions happened and then process those things into her advantage. Another great thing about Lorraine's abilities is to know what the Occultist is doing to Arne, so she can help Arne before the Occultist completes the curse. The last thing is the beginning scene... It is one of the best scenes that a director has ever made for a Conjuring film and it's debatable that it might be the best opening scene ever for any of the Conjuring Universe films. There might not be as many jump scares as the first 2 Conjuring movies or even the other Conjuring Universe movies, but that doesn't take away the fact that this film is scary.
In other words, Vera Farmiga's acting is what carries this movie.
If you watch this movie (which you should), this review of mine will not be a lie to you if you think it was.