The more I deal with scalable relational DBMSes (Spanner in particular), the more I doubt their usefulness even at large scale. Relational + fully-consistent ar

The more I deal with scalable relational DBMSes (Spanner in particular), the more I doubt their usefulness even at large scale. Relational + fully-consistent are always at odds with scalability. It seems like either you have a classic NoSQL use case and use that, or you shard at the application level rather than in the database. Could someone share a use case where you truly benefited migrating from Postgres/MySQL to Spanner/Citus/Cockroach, and there was no better solution? I'd like my hunch to be wrong.