Accordian Style Checkouts – Style over Function?

Accordion Styles Checkout are one page checkouts that expand and, optionally contract, the steps involved in checkout as the customer moves from step to step.
A customer would come to the checkout page and the steps: shipping, payment, final costs (tax)  are contracted.  As they move to step to step the steps expand.
As such, the process looks short which implies little effort to complete.  This supports the theory that customers won’t abandon the cart due to checkout fatigue (friction).
But does it?
Experiments have indicated it doesn’t.  In fact it can have a significant negative impact.
Why?  This kind of checkout is actually keeping the customer “blind”. They cannot see the next step until they complete the prior step. That is a bit like a multi-page checkout where they can’t see the next step until they get to the next page.
A better approach is to keep to the one page checkout with all steps shown but, through careful design of the page layout (user interface + graphic design), make it appear not as 3 steps on one page to one step on one page. You can do this by the omission of boxes, dividing lines etc. between the steps.
So before you jump on the bandwagon and convert to an accordion style checkout, make sure you understand the problem you are trying to solve and then ask yourself, is this the best way to solve it?