I suspect your 'question' here will soon be closed as a duplicate. Misunderstanding of the answer you linked aside, comments at ELU (and, I presume, elsewhere on StackExchange sites) are explicitly ephemera, subject to removal at any time. So the answer is no: moderators should use their best judgement when removing comments, but I suspect the relative value of the comments is not much of a consideration, because that value is highly subjective.
In the case you've cited, if the comments were truly valuable, they could've and should've been reworked into an answer.
From the help page: "Comments are temporary "Post-It" notes left on a question or answer." Note the "temporary". Also, from the same page: "Comments are not recommended for any of the following: .... Answering a question or providing an alternate solution to an existing answer; instead, post an actual answer (or edit to expand an existing one)".
See this meta question and its answer: Why was one of my comments deleted on this question? (also, request to add a feature to the site to be notified of post and comment deletions).
This meta question and answer may also be useful: Why are my comments deleted?. The answer is provided by a moderator, and is in my opinion more cogent and complete than the answer given for the first meta question I linked.
The answer at the first meta question I linked notes, mistakenly in my opinion, that comments "do not add value to the site". In my experience on this and other StackExchange sites, comments add the only value available, but my opinion is pragmatic rather than theoretic.