I think another reason is demand. Without blink a ninja is a pretty lame duck, if they want to be a tank anyway, which is their main role in pt. So in order to level past 13 and even make it to lvl 37 where you can use Ni, you almost _have_ to buy ichi. Thus why the demand is so high for that first stepping stone. Oh and incase you didnt know, ichi is japanese for one and ni is japanese for two
