You're right `virtmach` only works on things that are output from `compile` and maintaining the invariant that virtmach lisp uses those pointers isn't difficult to do in with how the evaluator is presented.

It gives virtmach lisp and scheme different ontology, but I can't think of any practical reason why that would matter other than it makes things a little bit more complicated. But, then again if I'm thinking practically scheme should be using hashed identifiers, and then there's no reason for them to have different ontology and conceptually we're right back where we started with virtmach lisp and scheme using identifiers as objects.