Are you worried about security in using them at all, or when reloading?
How about reloading through the app? Nobody else there, so no physical security concerns.
Looking through the app, I see where you can buy gift cards, but I don't see a reload option. Of course, I've never used one, so maybe it shows up when you have a known one.
Not quite related, but I also now see that you can buy their discounted restaurant gift cards through the app. If those could be digitally delivered, I'll have to keep that in mind the next time we are thinking of going out.