Where C* databases seems to fall down are point updates and in this case, requirement to implement your own aggregations.
For these workloads you are much better off (unless you are already running C* somewhere and are super familiar with it) with something like Clickhouse or if you need good slice and dice then Druid or Pinot.
Yeah, point updates are less than stellar, but for aggregation, it's fine unless you're really want adhoc low latency queries. For anything substantial you'd want Spark/Beam for aggregation otherwise, and the Cassandra model is really fast at loading up time series type data in parallel, and Spark etc. make it really easy to do. The tradeoff is just the high startup cost of those kinds of jobs.
