Pros:
They want it.
They can measure compute their states and formulate strategies using a program to give them advise.
Cons:
Harassment.
Not the intended play style.
Advantage over users who do not use the tool.
Use of addons that go beyond strictly parsing.
Game information is mined and collected.
Counter:
Harassment - No one would do that its against the rules on its own. - followed by calling players bad for their lack of stats on websites that people upload others parsed data to. so how could they be harassed their just bad.
Not the intended play style. - Its not needed but makes things easier. People want to play better but don't know how without hard calculated evidence from a computer program and script telling them as such. Also followed by arguments the the ones bring up that the game wasn't intended to be played that way are just bad players and could never do that content... further proving harassment.
Use of addons that go beyond strictly parsing. - but that would be against the rules, maybe? and also doesn't happen... often....
Game information is mined and collected. - You just don't understand how data works, it was already there... - no valid counter really made.
Please tell me where I misunderstood?