Just another streetlight
Predicting the "spectacular-lessness" of comets, meteor showers, eclipses, transits (of the non-Ford variety) and planetary conjunctions is prone to hype. Not so much because of what the astronomers, in their enthusiasm, say but in the way the inexperienced media go completely doolally when they have something extra-terrestrial to report.
So yes, hopefully this comet will be bright. Hopefully if won't be obscured by clouds for months on end. Hopefully it won't be washed out by the full moon or by being too close to the sun in the sky. However, for the vast majority of people even the moon at its brightest has to compete with thousands of streetlights - all pouring wasted light into our skies and turning what should be a spectacular night-time view into a dull orange glow.
Luckily the Normans, in their conquest, didn't have to worry about such things or their tapestry wouldn't have featured a comet at all.