The other currency shops all have buy buttons underneath them because they're built on the same code. I have on my list of things to eventually do that includes switching BB to the actual code our other quests use (like Wizard etc) and move the shop over to that currency too. It's not a thing I can do in 10 minutes like some of the other changes I did. :p

Yes! When I move over the BB, that's likely when I'll switch over crystal too.

I mean right now rank does matter to an extent. Higher rank shows more items. We've used the feature before. It's kind of like alchemy, how before they were all level 1 but we've been adding things at like 15, 20, etc. Future blue building items will def be higher ranked items. :)