I remember about a year ago when I was in a group. The BLM mentioned he was going to parse us. The group quickly fell from 8 to 3 people lol...
I personally dislike parsers because I'm about survival. However, I now understand why people use them; I hear Heavensward content is mostly DPS checks. Many people say that parsing makes the person play their job better. I honestly think it does not.
The way I see it, when you throw a parser at someone, they feel a certain way in that they HAVE to dish out a lot of damage. The con to this is that they tend to ignore, forget, or not pay attention to mechanics. A person who is NOT under the influence of a parser may deal less damage but s/he is usually one less person that the healer need to worry about.
*EDIT*
DC Universe has an in-gamer parser via the scoreboard. That thing makes all the wolves come out when there's fresh bait.