It should be possible to display meaningful messages.
Messages can only be displayed only on validation scripts at the moment. They were helpful for the user. If something is missing, they get the information, what is missing or going wrong.
On the OnCreate skript, it is not possible.
If something is going wrong, only a not very helpful message appears. If it is also possible to push messages, the failure can be found faster. Perhaps without always needing an administrator or support team.
With this, several scipts could be improved. Validations in OnEdit scripts cannot be done by the default validation rules of the item details.
Checks in OnEdit with a push message would be a great improvement in usability.