Why is it bad practice to call ref.read inside the provider body?

I am new to Riverpod and I dont get why it is considered bad practice to do this:

final myProvider = Provider((ref) {
// Bad practice to call `read` here
final value = ref.read(anotherProvider);
});

Why is this better:

final repositoryProvider = Provider((ref) => Repository(ref));

class Repository {
Repository(this.ref);

final ProviderRefBase ref;
}

Link to source