TYPO3 Core

There are installations where even if TYPO3 core or extensions suggest to use MyISAM or InnoDB you still want to force one storage-engine to be used.

There are cases like when for example a Galera-cluster is used, which so far only supports replicating InnoDB. MyISAM-tables won't be replicated across the cluster! But MyISAM can not be turned off in the database (since MySQL/MariaDB still use it internally).

https://mariadb.com/kb/en/mariadb/documentation/replication-cluster-multi-master/galera/mariadb-galera-cluster-known-limitations/