Same here, can't understand this limitation. You can't sell internationally which is crazy, I mean international clients prefer paying in PayPal because of trus etc. Just lost all my admiration for Shopify, huge issue. Rethink a lot of things.
This remains the stupidest, most mind-blowing issue I face. Like you I spent months building a business only to discover that there is an utter dunce making key development decisions, leaving many of us in the **bleep**.
It has been 3 years since this question was posted and Shopify has not solved this issue yet. Can we hire a developer to direct the shopping cart to another page other than the checkout page of Shopify ? or shall we just shift to other platforms?