You don't need any reputation to write an answer, however, you do need reputation to add comments to posts. You can always post comments on your own posts or answers to one of your questions.
Comments are meant for transient information such as improvement suggestions, clarification, or minuscule information. This also means that comments will be removed ...
I agree with both of you that unnecessary comments should be removed, but would actually rather encourage that people continue to flag such unnecessary comments, even if there is only a single one of them.
Unnecessary comments add visual clutter and cost visitors time to find what they're actually looking for. Globally seen, it is the vastly preferable ...
Comments have virtually no quality assurance while answers underly feedback mechanisms.
Comments are not indexed by search engines.
Comment answers unfairly steal the top spot without having been voted there.
Comments cannot be migrated to answers.
The suggested way to handle "answers in comments" is to steal them and post them as an answer ...