I think the advice is to avoid using it as a daily driver. If you only have nonstick and carbon steel pans, you might not want to cook something acidic in the carbon steel as it will kill the seasoning. If you have nonstick and stainless steel, you can use the SS for that.

On the otherhand, cooking eggs in nonstick might be easier/require less fat than working with stainless steel.

Nonstick also generally has a lower rated max temp, so avoid using it in the broiler...

All this is to say, it's a trade-off for convenience. With the right technique, or if you want to spend time to rebuild seasoning, you can pretty much use whatever pans you want to cook whatever you want. These types of non-stick pans are relatively new in the world of cooking.

> cooking eggs in nonstick might be easier/require less fat

I don't understand why anyone would want to cook eggs with less fat to begin with.