2. The product is better testable
A PCBA or printed circuit board must not contain any manufacturing defects. Therefore, a PCBA must be made testable. Before you start producing a prototype, write a Test Specification. Here you will find how to test all the functionalities of your PCBA. To make the PCBA easy to test, add test points to, for example, circuits and power lines.
While writing the Test Specification you will probably discover a lot of points where you want to add a test point. Later, when the product is made in larger batches and the product is automatically tested by, for example, an FCT, these test points come in handy. This means you don't have to place them in all kinds of places where it no longer fits. The manufacturer of your test tooling does have restrictions for the spacing of, for example, a bed-of-nails. So once again: consult with your manufacturers in advance.