Regional settings allow you to view the asset information for a particular region / locale - whether it be language, currency or anything else that is configured in the Metadata settings.
If Metadata Variants are configured for your project, you can view the asset according to a selected locale - including language, currency or anything else that is configured.
For example, if a project uses English and French metadata or tags in each language, you can use this setting to view the information corresponding to the selected language.