Hi,
All HikaShop pages you need edit through HikaShop Admin Panel, Gridbox Editor is working only with Gridbox Pages.
We have customers which building eCommerce websites in Gridbox + Hikashop. Pages, such as: Home, About us, Contact us, etc. they are building on Gridbox
And also, Gridbox it's not just a Page builder, it also allows you to change template style: header, footer, body, typography, which will also affect on Hikashop pages
Regards,