It's an easy template to work with. There's a generous bleed area.
What I don't know is where their cut lines line up. Since they do give that generous bleed, I suspect that the cut edges of the cards butt up together, so that trying to use a design that extends beyond the edge might be a fiasco of overlaps.
If the cuts don't butt up together, but are spaced some distance apart one might be able to do an edge to edge design, but you'd need to ask someone directly first. It's probably not something you'd want to risk flying blind on.