yes, you could remove the intermediate mesh it's just to make simpler the update method also you can create any shape without the main app having to know in which order to add the points.
try removing the update method and creating the mesh in setup as i said that should give you much better performance.
in any case you should also measure the usage of the gpu, the easiest way to measure the overall performance is to let the app run without fps limit, by disabling vsync with ofSetVerticalSync(false) and see which version has more fps
