HikaShop vs. j2 Store

-- HikaShop version -- : 3.2.2
-- Joomla version -- : 3.8.3
-- PHP version -- : 7.1.12

Hi guys,
as we know some of the mains difference from HikaShop to j2 Store are:

1 - j2 Store uses the default Joomla articles as its products . It can also be integrated with other content construction kits (CCK) like Sebold K2, Zoo and SobiPro.
In HikaShop the only why is to add an HikaShop product to a joomla article . But now, we know that Hika team is working hard on new Hika API and its own REST API.
Will it means that we can expext any good news about this integration point ?

2 - The j2 Store Bookings and Reservations App is something that real missing in HikaShop.
Do you have any suggestment to optain the same result ?
Do you have any on your RoadMap ?
Do you have any suggestments on How to develop / add something similar for HikaShop ?

Hi Nicolas (always thanks for your detailed answers),

2 - Many Thanks, I have to investigate and test a little bit more before to reply to you. I'm too interested on it and you know I'm collaborative.

1 - Thanks for the API Rest explanation, I know that, but I also red somewhere here about a new HikaShop API. This is why I asked.
Right now what I'm looking for is How to create content. Let me explain thinking on a front-end product create/edit and with the intention to find a good solution / compromise having from you any suggestment:

- Let me say that what you suggest me is how to Display HikaShop fields into Joomla Articles (and CCKs): User should create a HikaShop product, then create the Joomla Article (and/or Seblod Article) adding HikaShop tags.

- User need to create the HikaShop (hidden) product directly during its Joomla Article / Seblod Article creation.
As you can see on the j2 Store / Seblod guide (the method do not change from the standard Joomla Article), j2 Store solve it adding a selector to each Joomla Article / Seblod Article: Do you want treat article as a product ? Selecting yes all the j2 Store product fields creation are shown to be configured in the same page. In this way, all that are related to the product are organised in one page. When filled the user save the page and the connection is yet made.
For this point I asked you about an API. Create a Joomla plugin and /or a new Seblod Field to add to Articles the "Do you want treat article as a product ?" selector is not a "problem", the problem is to be sure to add the HikaShop Product creation fields in the right and simple way (thinking also in HikaSerial, HikaSubscription and/or HikaMarket solutions).

I think that this feature will improve too much the HikaShop potential. If an "API" is not available, Please, Do you have any suggestment on How to obtain the "same result" (also with temporally hibryd solutions like a link that open a new window, adding an iFrame to the page etc.) ?

PS I sent you an email