IQueryAttributable : use IReadOnlyDictionary instead of IDictionary

[nk54]

Hello, to work with Shell, we can pass argument while navigating from Page1 to Page2.

The IQuerryAttributable interface can be implemented to access to the argument.

My question is, why do we get a IDictionary<string,object> instead of IReadOnlyDictionary<string,object> for the parameters ?
Is there a scenario where you want to add parameter in ApplyQueryAttributes of Page2 whereas the parameter was given by Page1 (or its view model, you get what I mean)