From a commercial point of view, I would venture that this provides far far worse margins than building yourself and going through Lulu.
From a design point of view, I'm in no doubt that this gets its arse kicked all over the shop by tons of options out there.
Could this be an accessible, functional tool for vanity press publishing?
Let's say I polished up a rule set that I thought was fun, but didn't want to make into a commercial entity. Let's say I don't have design skills available to me. And let's say I find attractive the idea of getting this into a nice looking physical copy for myself, or maybe a few for my group, or even hold open the option for an interested gamer in Bolivia to get their hands on the self-same.