Comments are definitely "second class" posts. They're intended to be used to ask for or to provide clarifications to the main post that they're on. If they don't improve the post that they're on they might be deleted immediately, but you should always consider your comments expendable. Obsolete comment threads will be deletedObsolete comment threads will be deleted (eventually). Critical information should not be left in comments, but edited into a question or answer.
Remember that it's not just moderators that can delete comments. Enough flags from regular community members will automatically delete commentsflags from regular community members will automatically delete comments without moderator intervention.
All that being said...
Would it make people happy if 10k users could see deleted comments?
I don't see any harm in it. Worst case, it adds to the checks and balances for those situations when a moderator pulls the trigger on a comment thread too early. Best case, it allows 10k users to see the information and edit it into a proper post after deletion.