Well Calvin, we probably wouldn't invest in a bottle of Cloosterbitter if its sole purpose was to serve merely as a substitute for a superior liqueur. But maybe you can point to some cocktails in which the Cloosterbitter is a preferred or even essential ingredient?
Probably would never have tried it were I not unable to aquire the Chartreuse for two years (you know there's been a shortage?). Glad I did. Stick with the superior.