I wouldn't call it a filter, unless you use it for trivial tasks ("check that the input argument is not null, throw an exception otherwise"). Sometimes it is useful for trivial tasks though, because it may do things a human dev would be to lazy to do. It also tends to be faster at finding things (as in "change the color of the submit button on the address form to #f00").

But the real value is implementing known patterns that are customized for your application. Adding a field or a new type to a CRUD application, implementing an algorithm, rendering some type of object in a UI...