ObservableCollection not showing up in editor

Question

I'm trying to use an ObservableCollection in a ScriptableObject, but it doesn't generate any serialized field in the asset editor.

Here is my code:

[CreateAssetMenu(fileName = "Dictionnary.Asset", menuName = "dictionnary")]
public class TADictionnary : ScriptableObject
{
    [SerializeField]
    public ObservableCollection<TAVerb> verbs;
}

[Serializable]
[CreateAssetMenu(fileName = "Verb.Asset", menuName = "verb")]
public class TAVerb : ScriptableObject
{
    public List<string> synonyms;
    public string keyword;
}

I've read it used to not work on older unity version, but I'm using LTS 2022.3. So I'm not sure why it doesn't work.