The urge to "complete" a collection is sadly all that keeps some sections of the music business in business. Not sure there is really a lot of difference between this and the £350 box set that you can legitimately get for £250 or less within four months of official release. That's a planned for discount not an accident.
It's all dealers offering the lure of filling the gap in your collection you didn't know you had. All feeding an addiction. If a relatively innocent one. Though I do hear that Duterte is a big crate digger in his spare time and this time it's even more personal ....