Multivalued fields allow a single field to have more than one value. Microsoft added this capability to the most recent version of Access as well as to SharePoint. Many people believe that this feature violates data normalization rules, which call for atomicity of field values.
Atomicity means that a field should have one and only one value.
If a record in a table has a field that needs more than one value for any field, data normalization requires that you remove that field and make a related table for it. On that basis, people do not believe that a database field should have more than one value. On the other hand, simple lists do not have to follow such rules. Therefore, it may have been SharePoint's ...