We use the page approval for risk management, where several roles have to approve of an idea.
For this, we have a table where each role can give his/her assessment and sometimes, the idea needs to be updated (hence if the page approval is reset, the page needs to be reevaluated). However, by adding your assessment as an approver, the approval of all previous assessors will be reset.
It is really necessary to either have an option to have to page approval ignore part of the page (e.g ignore changed content inside a special macro) or to exclude certain users from resetting the page approval.
The 'comment' column is not a valid replacement, as comments are lost upon a reset.