How useful is the Bayeux Tapestry as a source for the events surrounding the Norman invasion of England?

The Bayeux Tapestry is unique and invaluable as an artefact of its time. It is not as simply as appears however and it is essential that we define its provenance and date. We must also understand the idiosyncrasies of its design if it's to take its place as a 'major authority for the events of the Norman conquest.' A point that must be addressed at the start of this essay is that the Bayeux …

…we know its provenance and date - are the two versions of events that resided in oral tradition among the Anglo-Saxons and the Normans. The Tapestry is as expertly crafted full of symbols and meanings as a sixteenth century Holbein, but it brings us no closer to the crucial point of whether Edward really did send Harold to William to give him the crown, and whether Harold did actually pledge the kingdom to the Duke.