TiDB is running core banking services too.

I think people’s idea of scale and operating at scale is limited to their experience.

You can get MySQL to run at any scale, look at Meta and Shopify. Operational complexity at that scale is a different story.

Distributed databases reduce a lot of the operational complexity. To take one example:

Try a DDL on a 5 TB table in any replicated MySQL topology of choice and compare it with TiDB’s Distributed execution framework.