What exactly is the problem with keyword cannibalization?

Selected answers from the Dumb SEO Questions Facebook & G+ community.

• 
  Rienzi Mosqueda: Imagine ranking for 5000with same intent kw vs 500 relevant kw.
• 
  Michael Martinez: " CTR/bounce rate/dwell time are NOT SEO factors."
  
  Which, for the record, they are not (except for personalization - and then only CTR seems to matter temporarily).
  
  "What exactly is the problem with keyword cannibalization?"
  
  What do you mean by "keyword cannibalization"?
  
  The search engines have no guidelines forbidding being listed twice in their search results, or even three or four times.
  
  Now, Google did change how it handles sites that are awarded Featured Snippets. They are only shown once. So technically you cannot have multiple listings if you`re awarded a Featured Snippet.
  
  So, what is being "cannibalized"?
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  Ammon Johns: I`m going to disagree there, Michael, but mostly over the word `SEO` rather than `Ranking`.
  
  CTR, Dwell-time (only on visits that bounce back to the SERP), and Bounces (but again, ONLY those that bounce back to the SERP, are all factors of search engines, Google in particular, used to rate, tweak, and refine their ranking algorithms.
  
  These are not `Ranking Factors` because this data isn`t applied to one site or one result, but rather, these figures go into changing the ranking factors for an entire search type or topic. A tweak to the algo affects all sites, both those that performed well and still do under the new algo, and those that get demoted by it.
  
  But these absolutely are SEO factors that a good SEO should be aware of, as they affect the search landscape on which we are to operate.
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  Michael Martinez: Ammon Johns I agree with you. Unfortunately most marketers don`t understand the difference between rating the algorithms and rating the Websites. The clicks searchers make on other sites for a query can still help a site that receives no clicks for that query (in the evaluation time frame) if whatever produced those search results is saved for future use.
  
  The indirect value of these analyses isn`t really what people are interested in. They want to know if they improve the CTR of their listings in the SERPs, will that help improve their rankings.
  
  To date, the search engines say it only helps with personalization.
  
  A recent example people can easily test for themselves is a change Google made to YouTube`s personalization. I believe (but cannot prove) they are using a new algorithm nicknamed EDAM (for end-to-end deep attention model), which takes the user`s recent click history into consideration.
  
  I have seen no evidence that Google is using anything like this algorithm in their general Web search results.
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  Dave Elliott: How are these things linked? I don`t get the premise.
  
  Keyword canibalisation is potentially bad because you are asking Google to pick which one of your pages it should rank for the phrase rather than having a bit more control over how the user goes through your site.
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  Ammon Johns: Simple, one of your pages will convert better than the other. With keyword cannibalization you run the risk of the less-converting page getting the search position that the better converting page would have had, because Google`s metrics are about visits, and use of their engine, not your profits.