What you describe is best practice for older versions of Cassandra with older versions of the Oracle JVM on spinning disks. And at this time Apple already had a massive amount of Cassandra nodes. Back when 1TB disks were what we had started buying for our servers. Cassandra was designed to run on large numbers of cheap x86 boxes, unlike most other DBs where people had to spend hundreds of thousands or millions of dollars on mainframes and storage arrays to scale their DBs to the size they needed.

Half a TB per node, which during regular compaction can double. And if you went over, your CPU and disk spent so much time on overhead such as JVM garbage collection that your compaction processes backlog, your node goes slower and slower, your disk eventually fills up, and it falls over. Later things got better and you could use bigger nodes if you knew what you were doing and didn't trip over any of the hidden bottlenecks in your workload. Maybe even fixed in the last few versions of Cassandra 3x and 4.0.