Sounds like an annoying card to use. It's a Discover card, so it's not as widely accepted as if it were a Visa, for instance.
Each load has a max of $50 (with a load fee of $1, that's a cost of 2%), and you can load a max of $250 per day, $5000 per month, but the card cannot have more than $1000 on it at a time.
It looks like you're able to load online with a credit card, though, so that's convenient. But with the high load fee, it's probably only good for meeting minimum spend.