I'm a former player, but played continuously from release for 11 years. This is undoubtedly ridiculously expensive, but the convenience of having your mail and auction house anywhere in the world - the value to certain players is immense. I think if I played still today, it would probably be a struggle deciding whether this limited time offering was worth jumping on - I certainly don't need it even a little bit, but when I want it, this thing would be incredibly convenient to have. Maybe that would just be the addiction talking. But when you spend all your free time with one game, you do feel a sense of good value relative to things like drinks at the bar or a movie or buying 1 or 2 full priced games a month.
But truly, the utility this provides for you and your guild is immense and impossible to replicate. They definitely shouldn't be selling mounts on the shop for $90. That's fucked. But compared to some of the video game devs selling weapon or character skins for as much or more, there IS at least a unique value proposition to the player. I guarantee there will be people with it the second it releases, for better or worse.