Of course the difference is intent. He won't look like a "pitbull off the leash" (this is pretty unfair to pitbulls, btw) unless he acts like one. Bottom line is, no matter what you use you will still face the same burden of proving that using it the way you did was lawful. Delica, dagger, machete, axe, scissors, gun, nail clippers, stick, bare hands, no difference.
The OP asked a specific question, and I did my best to offer a specific answer. If you disagree, that's fine with me. Oh, and what can a fixed blade, no lock, double edged, fine point, strong gripped, fast deployed, easy to use push knife do that a delica can't? I can't imagine, all I can say is if I REALLY had to defend my life with one or the other, I know which one I would pick. Here's to hoping and praying that will never come to the test.