There isn’t anything you would be missing out on if you change the device handler. The only difference is how the notification devices show up in SmartThings. The default way is for it to not show up in the “Things” list but to be able to select it in SmartApps. It seems that when they are created in this way, some external integrations (home assistant) can’t see them.
Changing the device handler as shown will make it so that the child devices do show up in the Things list as separate devices. That is the only difference.