Whenever I see questions about CAP as a useful thought exercise in distributed systems, it seems to originate from people trying to defend database systems that

Whenever I see questions about CAP as a useful thought exercise in distributed systems, it seems to originate from people trying to defend database systems that don't respond well to the realities of partition inevitably. That is people doing implicit or explicit marketing of some enterprise data landgrab telling you things like they can scale arbitrary SQL joins across distributed tables. Because large data sets do not teleport across the wire for merging. Foundation db, Cassandra, and kinda dynamo (I don't trust their new global replication) actually scale, but I've never used gcps db techs. CAP is imo one of the best distributed systems principles ever stated. It is simply state, compare to say the nitty gritty of say paxos vs raft. It is a very useful first principles exercise for deconstructing whatever harebrained claim some marketroid is foisting upon you.