Hi,
I'm not following you.
What do you mean by "In my shop I want my customers to directly go to the CPanel." ? I doubt that you want the cpanel to be the home page of your website and the users have to be logged in to access the cpanel, so it's not possible to directly display the cpanel when someone arrives on your website anyway. So I'm not sure what you want.
If a user is not logged in, this will directly take you to the joomla's user component. (component/users)
To be more precise, if you try to access the HikaShop cpanel while not logged in, you'll be redirected to the login page of Joomla so that you can login to access the cpanel. And if you don't have an account yet, you can click on the "don't have an account" link there, which will then redirect you to the registration page of Joomla.
The "Redirect Joomla registration to HikaShop" plugin is to redirect the Joomla registration page to the HikaShop registration page so that you don't use the Joomla registration page but the HikaShop one instead.