Stripe & Customer Migration

Hello! Long time lurker, first time poster :). I have a client managing her content on SS, but her ecommerce functions on Cratejoy. Now that SS has subscription options, I've convinced her to move her whole platform to SS, just for the simple reason of being able to manage everything in one place. (Her retention rates aren't great, largely due to having to manage customer accounts on cratejoy's platform, rather than her own)

Anyway, I've only just found out that we can't migrate her customer database into the customers section of her site. However, her current payment processor is Stripe through Cratejoy, where all of her customer data is stored as well. My question is, if we connect her already existing Stripe account, will the customer data integrate? Will subscribers need to re-subscribe to the products? Or can we do that on the backend? It seems rather silly that I can't just easily make this switch with a simple import function. Will I need to individually create new customer accounts from the front end of the site? If I do that will the customer accounts integrate properly with the existing Stripe data?

Any/all advice here would be great. I hate that my client is paying so much money every month to Cratejoy when SS is such a great option for everything she's doing.  

Unfortunately, I don't think that the Squarespace Subscriptions service is the panacea you are hoping for. At least not yet; this is an evolving product.

To switch to Squarespace Subscriptions, customers will have to re-subscribe to your products themselves. There’s no way to import subscribers or their payment details and you cannot add them yourself, even if you used Stripe. 

If you want their new subscriptions to align with their current expiry dates, you'll also need to ask customers to re-subscribe in Squarespace on the date of their renewal.

Thanks, that's pretty unfortunate. It seems so silly to build this functionality and leave out the ability to migrate an existing store.