How to restrict view datasource fields

A view is specified by a query and there are two ways to define the view query - add existing query or add datasources to Metadata node:

Both options deal with datasources. It is recommended to restrict datasource fields and return only the fields which are actually used. Unused fields generate useless traffic and decrease performance. Is such recommendation relevant for the view Metadata?

Hints
Analyse the view CREATE script in SQL Server Management Studio. You can also jump to the conclusion section.