The thing is, The Vampyre is ridiculous. It is a more concisely-written Interview With The Vampire with Lord Byron as the main character and the plot a strangely-paced version of Byron’s life. The framing device is basically pointless and the long section in which the protagonist-that-we-all-know-becomes-a-vampire finds out about vampires and is trapped by one is as predictable as in any generic vampire story. It makes some frankly strange choices (giving a notably large amount of narrative justification for Byron’s probable affair with his half-sister Augusta, for example) and somehow does a disservice to most of the historical figures it fictionalises.
However, I’m glad it exists. It’s only natural that it does, given Byron’s connection with the popular image of the vampire (and The Vampyre, the story written by Polidori and given a new meaning in this novel). Also, if it didn’t, there wouldn’t be a moment in fiction in which Byron tries to convince Shelley to become a vampire too by using the argument ‘think of all the liberty we could fight for’, presumably the main way to convince Percy Shelley anything is a good idea.
To be honest, there’s no need to read this novel. Watch the Horrible Histories sketch about how Byron isn’t a vampire, but just a pretentious poet. Then, maybe watch Gothic (1986) to see some trashy fiction featuring Byron and dreams and which, unlike The Vampyre, doesn’t make everyone and their mum a vampire (except Percy Shelley who Byron really wants to be a vampire, isn’t life unfair).