Bought this on an impulse since I've been looking for more card based generators, and it seems really useful on first read. As someone running a sandbox, it's going to be great for populating hexes.
I'm pretty sure this system could be adapted for a wilderness point-crawl style adventure instead of just dungeons as well.
Overall a lot of potential for tweaking, in addition to being very useable as-is. Definitely worth the $5.