And I'm inclined to believe it's a useful and quite informative grind, even if that's an unfortunate choice of words, considering how much he writes about martyrs.
This section of the book has been dealing with the period that he personally experienced during the co-reigns of Maximianus, Maxentius, Maximums, Constantius (father of Constantine) Galerius and Lysinius (names are a little flexible, not least due to the OCR occasionally failing as the book was digitised) when the empire was split into separate regions. He describes a period of heart-rending brutality, though not at all out of character with other times in the history of Rome, when an emperor was able to take whatever he desired without limit or restriction, experiencing insatiable lust and then unlimited fear and superstition.
The church in the period immediately prior to this round of persecution is presented as having gone completely off the rails under benevolent emperors, with bishops building empires, frequent heresy and internal warring. The persecution was described as though it was God's just retribution on the church for failing to worship Him. The need to please God - the word 'appease' God was used in the translation, though I have no idea how accurate this is in terms of Eusebius personal or the common church theology - was seen as the way to get the persecution lifted. One has the feeling of a system of religion not so far removed from Judaism with updated details, and not like a vibrant, Spirit-led 1st century Christianity.
Throughout the book thus far there is a subtext of an increasingly sophisticated system of religion being developed, with significant variations between different geographical locations due to the power and influence of individual bishops. Some of these variations seem honest and of good intent, some because of emotional direction or personal preference, some of mistaken intent that would allow itself to be corrected and some of deliberate malice for the purpose of acquiring power and wealth. Martyrdom was frequent and common, often performed with a breath-taking degree of cruelty, always presented as being desirable and something one should seek in order to obtain a better salvation. Those performing the various tortures were almost always seen as being willingly directed by demons, no longer in control of themselves, and subject to Satan's will. Self-harming and deliberate hardship was also seen as desirable, for example Origen's attempt at self-castration so that he might become a eunuch, in his mind emulating the apostle Paul, was admired.
It's interesting to filter these behaviours through an orthodox 20th century theology, but futile to view them with 21st century secular values.
This book has really opened my eyes to what I formerly saw as rather bizarre, highly superstitious religious paintings that depicted the righteous going to heaven while the ungodly were sent to hell to endure various unspeakable torments. What I first though were the products of a superstitious mind, I now rather suspect is a replication of many of the tortures that early Christians were forced to endure at the hands of those driven by demons. The torturers were being handed over after death to experience the very things that they had inflicted in life, and the experience of those early martyrs created such a strong impression on the church that, more than 1000 years later, the result was still being reproduced in art.