Are type fields pure evil?

Question

As discusses in The c++ Programming Language 3rd Edition in section 12.2.5, type fields tend to create code that is less versatile, error-prone, less intuitive, and less maintai

Answer 1

Aren't there costs associated to virtual functions and polymorphism? Like maintaining a vtable per class, increase of each class object size by 4 byptes, runtime slowness (I have never measured it though) for resolving the virtual function appropriately. So, for simple situations, using a type field appears acceptable.