All workflows are identified by targetKeyspace.workflow where targetKeyspace is the name of the keyspace to which the tables are being moved. workflow is a name you assign to the MoveTables workflow to identify it.
MoveTables has separate semantics than Migrate. MoveTables can migrate data from one keyspace to another, but both keyspaces need to be in the same Vitess Cluster. Migrate is intended as a one-way copy whereas MoveTables allows you to serve either data from the source or target keyspace and switch between each other until you finalize MoveTables.
MoveTables sets up routing rules so that Vitess routes queries to the Source keyspace until a cutover
While switching Write traffic, in MoveTables, is possible to set up a reverse replication workflow so that the Source can be in sync with the Target, allowing you to revert back to the Source.
However this requires that the Target can create vreplication streams (in the _vt database) on the Source database. This may not be always possible, for example, if the Source is a production system.
In MoveTables the tables already exist, just in a different keyspace. So the VSchema already contains these tables. While migrating, these tables will be available only after the Migrate is completed
Switching traffic is not meaningful in the case of Migrate since there is no query traffic to the original tables, as the Source is in a different cluster.