According to the site, "Quickly and easily connect a receipt printer, kitchen printer, cash drawer, and barcode scanner. Get your hardware up and running in minutes."
So, I'd assume you print the receipt to a receipt printer that you connect to the stand.
So it is a $299 plastic ipad stand with about $5 worth of magstripe-reading tech attached. My point is that this is being represented as a 'register reinvented' when in fact you still have to add on all the things you listed that make a register.
I haven't needed a printed receipt in years, I use Xero so even paying in cash with Square and getting an emailed receipt is a bonus instead of having to remember those 30 seconds to take a photo of it on my phone and log the amount.
So, I'd assume you print the receipt to a receipt printer that you connect to the stand.