I would think Larian is looking into alternate payment methods. I haven't really followed any kickstarter campaigns, but know at least a few also have a paypal option (not that that is really popular in Europe, either, AFAIK). Crate Entertainment set up pre-orders for Grim Dawn from their website with categories similar to the kickstarter tiers (after the kickstarter ended).
EDIT: There is a short FAQ at the bottom of the kickstarter page:
Quote
Will there be a way to support through PayPal?
Yes, we are working on it. As soon as it's implemented, we will link to it.
