Crafting is a handy skill to develop. Whenever you level up your crafting level you can create all sorts of different items that are important in the Runescape world. Crafting can be a profitable skill to develop, as there are lots of different items that you can craft that may produce a profit. Crafting is also important for quests because lots of quests require you to have a certain level of crafting to allow you to start them. Some quests don't require you to have a certain crafting level but recommend a certain level that would be a convenience to you, while others won't let you finish a specific part of a quest, or end the quest without a certain level.