Hi,
Well, it depends on the payment plugin you use and what PayPal decides to do to add that capability.
For example, with the standard PayPal payment plugin, the payment form is directly displayed by PayPal on their own website.
So there is nothing to do in HikaShop. Either PayPal adds that capability to that form or doesn't.
And it's the same for PayPal Express checkout, or PayPal advanced.
For PayPal Pro, maybe some modifications might be needed in the plugin supposing that the API supports it.
Basically, what will be necessary to support that will in most cases not require us doing anything. But since there is no technical information about how it will be added, it can't say anything for sure.