A historical novel about a Spanish fascist: Worth reading?

I've read the first two sections (now reading the 3rd and final) in Javier Cercas's 2001 novel, Soldiers of Salamis (a reference to the Persian wars of antiquity - no idea why this is his title). On one level it's pure and simple a piece of short historical fiction, recounting the adventures of a leader of the fascist party in Spain at the end of the Civil War (ca 1938), Sanchez Mazas, an accidental "hero" (he saw no combat and exhibited no particular bravery) who was lined up before a firing squad, managed to escape in the chaos of the mass shooting, survived but barely after a few days in the forests, was aided by 3 young men from the countryside, and survived in time for the success and triumph of Franco's fascist forces. Over the rest of his life, the families of the men who helped him would send him requests for amnesty for various Republican soldiers held captive, and he would always oblige - though he never saw the men who helped him again in his lifetime. He went on to be a leader in the Franco dictator ship, essentially their house intellectual, publishing many works of altogether mediocre literature. This material does not seem particularly promising, especially for non-Spanish readers who, like me, will be repeatedly confounded by complex history of the Spanish Civil War and its various parties and ideologies. What makes this novel worth a read, however, is Cercas's structure; as w/ so many Spanish-language writers of the past 50 years or so, he's interested in self-reflective, postmodern fiction. So the first section of the novel is entirely about JC's attempt to gather information to enable him to write the story of Sanchez Mazas, including interviews with surviving witnesses, tracking down documents (such as SM's diary) and official records, etc. The 2nd part is the historical narrative itself. The 3rd section is about the aftermath: JC publishes the novel and returns to his job as a newspaper reporter, which he finds a bit demeaning. He's assigned to interview Robeto Bolano - one of my favorite writers, in fact - and they discuss the book and Bolono's work and JC's foundering career - all of which has the ring of truth. So the novel seems to engulf itself - it's the before, during, and after of its own composition, which of course leads us to speculate on what's "real" in an narrative and what's fabrication. But that's an intellectual's pastime. More to the point: Why does JC feel compelled to tell the life story of a fascist and a long-forgotten pseudo-literary figure?