When a Redshift cluster gets too big: 1. Takes forever to take backups, create read-replicas, modify anything 2. Redshift clusters can still only handle X concurrent queries, no matter how big the cluster is 3. Also Redshift is dragging their feet on adding new features i.e. Active Directory support.
Snowflake clusters allow a theoretically unlimited amount of users to query the same tables in a database - so it scales up forever.
And each team can create their own "compute cluster" which allows teams to track and divide costs much more easily then trying to associate this-batch-user on Redshift with this-team/line-of-business.
Snowflake is well-designed for an enterprise environment where line-of-businesses need to share/access each others data but still have separate infrastructure. Redshift does not make it easy go between Redshift clusters.
Also Snowflake as a company is still hungry and is willing to add features if you pay enough
EDIT: However Snowflake is more expensive than Redshift
EDIT: Splitting data between two Redshift clusters was not efficient for us and trying to have the same table in multiple Redshift clusters requires you creating your own tooling and the data might not stay in sync so the only real option was keeping everything in one massive cluster