Anyway, some reasons:
* Draws together a wealth of material on databases and distributed systems that wasn't explained in a systematic, accessible way anywhere else. It provides a map to someone coming to this hard-to-navigate area for the first time.
* Great balance between being conversant with the academic research (without being too abstract) and being practically applicable (without being too tied to details of particular technologies)
* Shows underlying unity and concepts of very different data technologies, e.g. why classic relational database write-ahead logs and replication are very similar to streaming platforms like Kafka
* Subjective, but it is very clear, accessible, and well-written. This is very very hard to do and quite rare in technical books.
It's my favorite technical book of the decade and my first recommendation to anyone who asks me how to really "level up" as a senior engineer.