Tattoos are shadow, ok i agree with that but when u make max lvl tattoo it will be good to be able to "refill" the tattoo with materials/adena or whatever bcz after 6 hours of usage will need to make another tattoo from lvl 1...
Thats the idea.
The 6h duration is plently enough to allow you to play pvp/pve and meanwhile prepare yourself for create a new tattoo to replace the old one.
The whole system pushes economy forward as makes mats gets consumed and traded between players.
It also makes the player see interest in the PVP Area of GoE to obtain Vials (and enhance their gameplay experience with entertaining solo PVP and party PVP in that dedicated area)
Drake, PM :P