This is a great old-school effect.
Though I should point out the effect is already available as an asset for Unity for free on GitHub and on the Unity Asset store:
That does use custom shaders rather than purely script based. Script based is useful for OpenGLES 2.0 projects, but after than the shader based approach is significantly preferred for performance reasons. It also more correctly handles z depth which your approach does not appear to do which will cause problems when trying to put your effect into a 3D scene. That alone makes it a non-starter for me if I was someone who was looking at using the asset for anything.
There is a similar effect that I’ve not seen as a Unity asset anywhere though. Having both your lines (with it properly projecting back in 3d space) and this glow effect might make it a more interesting asset. Or if you’re just looking for something else fun to implement.
In the past I’ve spent time trying to do this in a purely shader based approach, and I got close, but I never found a clean way to handle the corners I was happy with, so a script based approach is still useful.