I would like to know, what does it mean and what is the benefit of having curated, tested and certified node modules?
Why do you buy cereal from the same brand every time? Why do people stick to the same brand of cars every time they buy a new one? Why are people happy when a product is certified by the FDA or whatever relevant authority?
Predictability, stability and security, mostly.
The NPM archives are open, meaning everyone can submit changes, also unstable ones, or those introducing security loopholes in your app. When only a proven selection of stable and secure modules is available to your app, you run less risk of hacking.
The concept is similar to Debian's Stable distribution, which doesn't change packages for years and just backports security fixes.