Yes, it's a thing. It's not that I can't see the use in it, we have even recommended it in the past where it was a worthwhile investment for our customers as they celebrated a special occasion at their place.
It is the metaphor I associate with it that intrigues me. When I see grass paint, it represents the covering over of what something truly is to look more presentable. To me, it symbolizes the cloak of the modern day pharisees within our churches. God knows our hearts, and He will not be mocked. So when we put on a fake persona of holiness, speak Christianese to those around us, or live with hatred of others in our hearts; know that you may hide it well from those sitting next to you in church, but you have already been found out.
What grass paint is designed to do is literally paint your grass a rich, green color. Imagine taking off your shoes to step onto that beautiful patch of lawn to relax only to be stabbed repeatedly in the feet by the hardened blades beneath. It adds a facade of beauty to what is ugly. The blades have not changed at their root, they are still the same, but are masquerading now as healthy and beautiful.
So to it can be with our lives. It is a dangerous position to actively put yourself in and choose to live by the world and not truly for God. Your heart can be ugly while your outward persona is beautiful and desirable. Please check yourself and examine your own life against the Bible to ensure you are not merely living behind a cloak.