What filters do, and why a view has a default
A data view starts with every row of its type — every case, every site, every task in the project. Filters decide which of those rows the table keeps. A view of open tasks, of this month's inspections, of Small sites only: each is the same table with a filter on it.
Filters appear in two places:
Apply Filters, the last step of the wizard, sets the view's default filter — the rows everyone sees when they open the view. It is part of the view's design, like its columns.
Manage Filters, on the view page, lets anyone reading the view narrow it further for themselves, and lets a manager change the default.
Leaving every control empty is a valid choice: the view then shows all rows. Filter when the reader should not have to scroll past rows that do not concern them.