For many of the people who are getting “novelated biographies” in the Spanish market there are no “serious” ones; often the written materials available about that person are almost nonexistant. So long as they follow the convention of putting a Characters list at the start, listing (hist.) vs (invented), I’m all for them. Note that a novelated biography is still not quite the same as historical fiction; the writer is “filling the holes” but doing her best (usually it’s a woman) to avoid distorting what solid data is actually available.