We used it in January and it is exactly like a gift card but restricted to dining. It was emailed to us on check in day (it came through when I took my phone out of airplane mode on arrival at MCO along with our room details) and you either use the barcode in the email or save it Apple wallet and use it from there. I can't see anything in the email about adding it the room for charging though. They deduct the value of your meal and each time your receipt will show you the remaining balance on the card.
Print that list of participating venues before you go (or bookmark it) as they don't give you anything with the card. I had seen it before we went, but couldn't find it again whilst away so was always a bit tentative when going to use it. I can't think of any restaurant or food cart that we tried to use it at that rejected it, the only time was when we went to buy a drink from somewhere at the front of DHS that sold souvenirs too and they couldn't get it to work. The value went a lot further than I thought it would though so it was a good thing to have!