Technically, they will accept it. However, if you think in terms of how admissions reads, they are used to one or the other, not the combination. It will stop them in the reading process, which is something you do not want them to do. Cover letters usually are only scanned unless asked for. Academics, then GMAT, then application, then recommendations.
Applications are like the building of a snowball of information on applicant.
That is why you want to offer new and different information as you go along. Keep the AdCom reader involved. I have read the prior chat transcripts - I remember you discussing aspects of your professional experience, community service, values, etc. The biographical information cites the community service, professional experience. Values are discussed in essays.