Question: value is not effective for activating Composition of operation %Nabla

I read  help document of %Nabla :

%Nabla is the inert form of Nabla, that is: it represents the same mathematical operation while holding the operation and checking of arguments unperformed. The expansion rules defined for Nabla, however, also work (are implemented) for the inert %Nabla. To activate the operation use value.

with(Physics[Vectors]):
(%Nabla)(f(x,y,z))
value(%)

 

But if I want to use Composition function , is it not useful? why? how to do?

(%Nabla@@4)(f(x,y,z));
value(%)

we know that:

(Nabla@@4)(f(x,y,z))

 

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