You can use these propterties in combination with default search values.
It could be usefull for instance to use a default search value on an overview of contracts showing only contracts of a specific year. You can then choose whether the user is able to see the default search value (read only) or not (hidden).
If you want the user to be able to use the searchfield then this property should always be set to 'normal' (which is the default value in the business modeler)
When you always want to have a overview with the transactions of the current day.
In this case you will set the DateTime attribute to a token: CurrentDateTime.
Now you have the transactions of the current day.