Yeah I was wondering why it was just sitting there too, and was going to ask if it was just transferred to that tank, makes sense now. In any case you'll definitely want to see a video of it swimming to make sure its gait is proper before considering to buy.
Insofar as quality of this BB, I'm very reluctant to dish on a fish, esp. as overall available quality locally will be different there, unless you hand pick and order one from overseas. It's also often hard to tell about coloration with Aros as it depends so much on lighting -- even more so with BB's, where the blues/purples/greens actually show better in more subdued lighting.
That said, from that short video, I'll be honest in saying most would probably classify that particular BB as about medium quality -- so if the price is also around medium level, it'd be seriously worth considering. Pearling (near tail fin) could be better pros would say, but it has some nice colors when in closer and lighting was better, but whether it completely crosses over (6th level; now mostly at a respectable 5th level) is kinda 50/50. Would certainly have a higher chance to do so in that big, sunlit pond you have, it has potential to be a very beautiful fish with your good care.
In summary it would be nice if you had other local choices to compare with, but if hard to get there, price was right (and looks healthy/robust after settling in) I'd say go for it.