Perhaps he wants to jump through hoops to avoid function pointers, even when doing that in C++ for optional functions like is done in the VFS requires gymnastics:
https://godbolt.org/z/4GWdvsz6z
That is the closest I can get it to implementing an optional function via a C++ class member function instead of a function pointer. It is not only insane, but also masochistic in comparison to how it would be done via function pointers: