I think one of the maybe less talked about benefits of distributed SQL is support for nearly transparent rolling upgrades of the database with very little impact to a running workload. Spanner is best in class at this.
Major version upgrades, HA, multi-master, sharding and georeplication are all stories that are not as out-of-the box simple as they should be at this point, IMHO. Then you layer on all the ways devs tend to abuse postgres (stored procedures, pubsub systems, re-indexing hot tables, etc) that will need hours and hours of debate + meetings + committees + design reviews + more meetings to settle. When all along the team probably could have just written the data to something like Firestore and been, like, totally fine?
I think one of the maybe less talked about benefits of distributed SQL is support for nearly transparent rolling upgrades of the database with very little impact to a running workload. Spanner is best in class at this.