Alchemy is used for creating Potions, Scrolls, Manastones, Spellbooks and Orbs. Alchemy is a good money maker since people will always be popping potions, scrolls and of course always be needing Manastones. The Spellbooks and Orbs are just "Extra" goodies. Eventhough the last two items seem more driven for Spellcasters, Alchemy is a good profession for anyone since everyone.
The main thing that is great about Alchemy is not having to find other players or deal with other players to get Potions and Manastones. The only downside of Alchemy is collecting all the materials for this profession tends to fill up your inventory fast. If you can deal with that, this is a perfect profession for you!
NOTE: Alchemy is great for any class.