There may be cases where you would want to create a frontend component for a control panel.
As long as you just want to have a UI for registry entries like for example a vocabulary for a choice field, it is indeed only necessary to configure a control panel for the backend, with the extra registration for the frontend:
from plone.restapi.controlpanels import RegistryConfigletPanel
@adapter(Interface, Interface)
class PloneConfRegistryConfigletPanel(RegistryConfigletPanel):
"""Volto control panel"""
schema = IPloneconfSettings
schema_prefix = "ploneconf"
configlet_id = "ploneconf-controlpanel"
configlet_category_id = "Products"
title = "Ploneconf Settings"
group = "Products"
If you want to provide a more sophisticated control panel for managing content data and/or user data, then a frontend component comes in handy.
This would need an additonal route and this being added to config.settings.controlpanels