Some vendors use term "monitor", which is literally fancy term for "detect", nothing else, and as @PhoneBoy said it would be allowed and prevent would block the traffic.
Put it this way...I say same thing to any customer. If you are not sure or clear on what profile to use, just stick with optimized and modify it, so it only uses IPS, if you dont plan to use AV or AB blades.
It would simply save the profile as Optimized (clone) and then you right click on the threat prevention policy and select that profile (you can see example in my lab, I just gave it another name)
Andy