Let’s pretend for a brief moment that Vriska isn’t completely crazy. She is on to something in that heroes often are responsible for creating their greatest enemies.
Batman dropped the Joker into the vat of acid that drove him insane.
Half of Iron Man’s enemies us technology that he developed.
Lex Luthor swore vengeance after Superman made him bald (Yes, really. Modern retelling usually skip that bit.)
So Vriska is building the kind of “personal mythology” that paradox space loves to throw around in this game.
The obvious problem is that’s you know… not a good thing. That’s not something heroes set out to do, and when it does happen, it makes their lives more miserable. They have to live with the fact that they’re indirectly responsible for all of the carnage caused by the villains they helped create.
Empathy is a foreign concept to Vriska, so she doesn’t have that problem, but there are plenty of good selfish reasons to not create an unkillable enemy. Like the fact that you now have an unkillable enemy you fucking moron.