[kazinator]

The short answer is that the existence of multiple dispatch isn't motivated by the visitor pattern.

Moreover, multiple dispatch isn't obscure at all.

C++ has it, but only statically, for instance, in the form of overloaded functions. C++ chooses a function overload by looking at the types of all parameters and arguments.

Multiple dispatch is similar, but the run-time types of the arguments are used.

This is broadly applicable in making all sorts of situations nicer.