I might actually do the latter (you get gold - well, probably silver for tokens) - that's a pretty good idea. So if you have everything from a boss, you still get a small sum of money as a reward. Thanks :3
As for making tokens buyable with gold - I kind of like how you have to complete certain quests and kill bosses for them - I imagine it entices players to actually go out and actually visit dungeons, instead of - for example - killing Cladt over and over again for easy gold. ;P