I have been stocking up on plenty of halloween gear, when today I noticed that the tonics you get are account bound? Why is this so?
In the original Guild Wars, tonics were a huge facet of the in game economy. They were incredibly sought after, especially rare event ones, such as Halloween.
Not only do tonics serve as a symbol of achievement, but they are also rewards that can be gained by ALL players. Majority of the rewards available have high level requirements, as well as large amounts of dedicated time to receive them. These high-end items are far out of reach of lower level characters. Tonics on the other hand are garnered purely by participating in the Halloween events, and are more easily gained by low level and high level characters alike.
By making tonics account bound, it makes them less accessible, and practically removes them from play outside of the event they are gained in. In Guild Wars, you could receive a tonic from an event, and hold on to it for some time, waiting for its value and rarity to increase. At some point later, you could sell said tonic for a hefty price, or use it to become the talk of the town (or district if you will).
Without the ability to trade, players have minimal incentive to actually strive to get these tonics, especially the Everlasting versions.