I do understand the question. But you're evaluating Christus Victor under assumptions that don't fit it. Penal substitution assumes that it is God who is our accuser. Only Christ's death allows him not to accuse us. Christus Victor assumes that it is Satan who is our accuser. That is, after all, the original meaning of Satan. If Satan is defeated, then the whole system of law and accusation is defeated. This is starting to sound a lot like Paul, right?
"Who will bring any charge against God’s elect? It is God who justifies. Who is to condemn? It is Christ Jesus, who died, yes, who was raised, who is at the right hand of God, who indeed intercedes for us." (Rom 8:33)
This does not mean there are no consequences for sin. For Paul's take on that, see 1 Cor 3:12
"Now if anyone builds on the foundation with gold, silver, precious stones, wood, hay, straw— the work of each builder will become visible, for the Day will disclose it, because it will be revealed with fire, and the fire will test what sort of work each has done. If what has been built on the foundation survives, the builder will receive a reward. If the work is burned up, the builder will suffer loss; the builder will be saved, but only as through fire."
Personally I don't think Christus Victor alone explains Christ's work. Jesus does see himself as defeating Satan. But I believe that through faith in him he transforms us.
"For if we have been united with him in a death like his, we will certainly be united with him in a resurrection like his. We know that our old self was crucified with him so that the body of sin might be destroyed, and we might no longer be enslaved to sin. For whoever has died is freed from sin." (Rom 6:5)
The Words of Institution talk about Christ dying to establish the new covenant, in which the Law is written in our hearts. Heb 9 and 10 also see his death as a covenant sacrifice.