Well, keep in mind that VEs are mostly registered for interfaces.

I understand your point of view but I think the fact that we take into account the intention of the user to declare a particular semantic with a type makes sense (let's put aside the fact that it allows some non negligible optimization).

If you choose the semantic of a bag then you can't expect HV to consider your element is an ordered list.

I think, in your case, declaring your own value extractor for your very specific usage is an acceptable trade-off.