Is there a way to purchase items from the Medal Trader in bulk?
Solution 1:
In menus that allow you to buy variable amounts of items in bulk or otherwise, the scrolling control tips at the bottom of the screen usually indicate that you can do so. For example, this is part of the bar when you're purchasing weapons from the console in your room aboard the SBC Glocken:
However, when attempting to trade medals in for rewards in the SBC Glocken Lobby, these controls do not exist:
Therefore, it's safe to assume that you can pretty much only do the whole exchange manually.
(Screenshots from the PC version, but I imagine this interface doesn't have too many major changes on the console release.)