I was not referring to camping Dark beasts as slayer training because you'll most likely not get a bow drop while on task. Camping them as a money-making-method rather than crafting runes after you've hit 99 rc as Jebrim suggested...how could that be bad? After all, any rc xp after 99 is "xp waste" assuming your goal is all-99. In that case, the range/magic xp from cannon-alching is better, and the profit/hour may very well be at par with rcing. If your goal would be all-200m, rcing is obviously better.