I love that metaphor in how it applies to testing because it's basically saying that choosing the right testing strategy is the same kind of choice you'd make when choosing a brush for painting a wall. Would you use a fine-point brush for the entire wall? Of course not. That would take too long and the end result would probably not look very even. Would you use a roller to paint everything, including around the mounted furnishings your great-great-grandmother brought over the ocean two hundred years ago? No way. There are different brushes for different use cases and the same thing applies to tests.
This is why I created the Testing Trophy. Since then Maggie Appleton (the mastermind behind egghead.io's masterful art/design) created this for TestingJavaScript.com:
In the Testing Trophy, there are 4 types of tests. It shows this text above, but for the sake of those using assistive technologies (and in case the image fails to load for you), I'll write out what it says here from top to bottom: