The question title is rhetorical, and I expect most people's opinions will be in between the two extremes presented. Here's a summary of some of the pros and cons of the Community Wiki system as we've come to know it.
This is a big post, so please preface your response with an answer to the following question: Do the benefits outweigh the problems?
Stereotype: CW posts are for the selfless benefit of the community, don't be a rep whore.
Community Wiki Posts:
- Encourage community participation -- Community Wiki questions invite the participation of the entire community (those with >100 rep)
- Improve the overall quality of the site -- They allow for the rapid accumulation and careful vetting of information by many contributors.
- Allow the best content to be consolidated in threads with many answers -- When a question has a large number of answers (15 or 30), converting the entire thread to community wiki allows the community to participate in improving the content of the question and its answers, so that the best information can 'bubble' to the top.
- Open edit-prone posts to more help -- When a post has been edited a large number of times, that post can likely benefit from the input of others to improve its quality.
- Are immune from selfish attachment to rep -- Community Wiki questions, as they are owned by the community at large, do not accumulate rep for an individual, but exist solely for the benefit of the community.
- Show good faith -- Marking your question as community wiki voluntarily is seen as a sign of good faith, and can improve your post's reception under certain circumstances (such as subjective questions or polls).
Stereotype: The CW system is flawed and easily abused, and we deserve to earn rep for our contributions.
Community Wiki Posts:
- Deny contributors the reputation they worked for -- Community Wiki posts deny the original poster the ability to accumulate rep, which in some cases can be be seen as unfair.
- Allow others to edit an individual's posts too soon -- Community Wiki posts force the original poster to allow a large segment of the community to edit their contributions, which may be contrary to their wishes or expectations, particularly when the post is converted by one of the automated mechanisms.
- Confusingly still award badges -- Community Wiki posts still accumulate badges for their originators, which confuses the issue of whether they are really selfless contributions to the community or not.
- Punish contributors who improve their posts with many edits -- Posts are forced into community wiki after ~6 edits, which can be seen as unfair by those who are diligent about improving their contributions, and which some have alleged can lead to gaming of the system.
- Discourage asking questions which are too popular -- Threads are forced into community wiki after a large number of answers, which can be seen as an incentive to ask questions which are just popular enough to gain rep, but not so popular as to get too many answers.
- Can't be switched back -- The switch to community wiki is permanent, users who unknowingly or accidentally switch their post to CW cannot undo their actions and may be disappointed at their lost opportunity to gain rep.
- Discourage potential answers -- Some participants feel that having a Community Wiki question discourages potential answers, because answerers can choose to participate instead on questions where they have the possibility of earning reputation.
- Are demanded by some users when the contributor may not agree -- Some participants feel "bullied" into switching to community wiki mode when they do not agree with the opinions of those who think their post should be voluntarily switched.
- Are seen as a "free pass" to post useless junk -- Others feel that rather than calling for some content to be marked as CW to gain acceptance, that such content should be disallowed entirely rather than permitted by virtue of being CW.
On that note, should this post be CW? Or is it useless crap that I shouldn't have posted in the first place? :)