Why? Because it discourages potential buyers from the promo and less buyer means less money for spiral knights. This would have been some what acceptable if the boxes where acquired with every 10 dollars purchase but not for buying it directly yourself.
Let think about the last promo, it had unique items similar to this promo except it some of the percentages out of any prize box. So why suddenly bring back a promo (with one new item) with horrible odds.
Spiral knights is a great game, it just has expanded in the right areas. If funding is an issue I'm sure the community will be will to help in investing in the game so as long we get something worth while in return.
Why not allow they player to have a choice regarding the inclusion of these items in the boxes? If the ticketed boxes sell more then keep them, if the non-ticketed ones sell more than keep those.