Chayenne's key is extremely expensive and it easily reaches even 80kk on optional-pvp worlds or 50kk on Antica. But if you have lvl 40+ chars, someone willing to borrow you the key (not a problem if you have your own), time, and someone's assistance to do the quest, then... Go for it. It's just kind of time-consuming and requires some effort.
Personally, I've never had this key, so I'm not able to share my personal experience. Nevertheless, there is and there will always be a market for music boxes, so the idea is nice overall.
+ I'm not willing to invest in it. I've got a feeling that they can make it lootable in some years again, but that's just me :P