You remove all doubt.
I understand fully how to use the path tool to create "vector art".You had to posterize to get it started (or at some point early on). After that i'm sure you spent many hours mapping the edges and tweaking it, but to say you DIDN'T posterize is flat out incorrect. More accurate would be you didn't "just" posterize it.
Vector art allows you to scale the image to any size without loosing quality to pixelation. You could blow that thing up to 100 stories if you wanted to.