Why need to wrap a list for serializing it?

This should be an odd question but i need a explanation. Why i need to wrap my List of gameobject for serializing it?

Why i can't access the public field list into the inspector in this way?

Code (CSharp):

1. [SerializeField] public List<PickableTestObject> pickablesInRange;

It's so smart, intuitive and clean serialization, but if works with variables, why should not works with list?

I search on EVERY post and everyone turn out with a lazy solution like this:

Code (CSharp):

1.  [System.Serializable]
2. public class UglyWrapper
3. {
4.       public List<PickableTestObject> pickablesInRange;
5. }

It's so bad and ugly to create a class only for serializing a list.
I would know if I have wrong or not understood something ( i already know the "Because you can serialize MonoBehaviour class" concept)