The scenario is just an example of where it could be useful, but what you describe isn't something that is unique to patching the vtable - it is something that can happen with any form of function hotpatching, e.g. a library might use its own functions and some of those might be inlined by the compiler, so if you try to hotpatch one of those functions not all uses of that function will be replaced with your own.

This is something that you should have in mind when hotpatching in general, but that doesn't make hotpatching any less useful.