At first I thought “WMS & CO” was the stationery shop where the set came from, and marveled that the set came in a hand-made box. I dug a bit and found out that no, the box is just a generic storage box, albeit a $35 hand-made generic storage box that happens to fit the stationery set perfectly. Therefore, the inner box is exactly as baffling as the outer box if there is some meaning or message being conveyed by the branding – but just as likely they were selected for the fitment dimensions. I choose not to over-analyze such things. I’ll settle for appreciating how nicely everything fits together. (:
Currently in the earholes: 
I thought you’d like the packaging :) The WMS&CO box was made to hold their chipboard cards and envelopes. I do have the set of boxes you linked to that I intended to use to store correspondence cards, but they weren’t quite the right size and I worried the corner staples would not hold up to overstuffing. I ended up having to have boxes custom-made instead.
The Feel Good Skin Club box held some promotional products. It fit the WMS box so perfectly that it would have been a shame not to reuse.
That’s very very cool.