[Panzerschrek]

> by welding a vtable onto every type

It's not true. Virtual methods table is present only for classes with at least one virtual method. Learn C++ properly before doing such claims.

[tialaramex]

The context you snipped is about dynamic dispatch, that is what you - as someone who has "learned C++ properly" apparently call "classes with at least one virtual method" and indeed the earlier comment calls "virtual interfaces".