Why Use an IPS if Only in Monitoring Mode?

Here is a link to a commercial that describes the conundrum here:

https://www.youtube.com/watch?v=6ZK01lEepc8

Along the LifeLock point here is that many orgs monitor for intrusions vs stopping them.

Now, a misconfigured IPS can bring the train to a halt, but, that is why you "smarten" said IPS before you really start blocking traffic.