I would say that in the specific case of this article (talking about passing pointers to managed objects to C) it is easier without a tracing GC simply because

I would say that in the specific case of this article (talking about passing pointers to managed objects to C) it is easier without a tracing GC simply because reference counting doesn't ever move the object and so pointers won't be broken (except, as the author shows, if you let the only reference go out of scope before you're done using the pointer). A GC language _may_ implement pinning to overcome this, but not all do.