Why use Spellcraft when you could just use Detect Magic?

[The Emortal]

Am I missing something, or is Detect Magic just spellcraft that always succeeds?

[Whale_Cancer]

You are, indeed, missing something.

Detect magic doesn't always succeed.

You need detect magic (or any of the detect magic+ spells) AND spellcraft to identify an item.

Spellcraft doesn't let you see magic auras.

[LazarX]

You still need the spellcraft skill to make the rolls that give you things like spell and item identification.

[Avatar-1]

Detect Magic will detect magic an item, but not what the item is.

Detect Magic first, then a Spellcraft check will tell you what that magic item is.

Spellcraft (without Detect Magic) will tell you what spell is being cast.

[Ninja in the Rye]

In the BB rules Detect Magic does indeed tell you what a held magic item is/does. Probably done (wisely, IMO) to keep new players from being frustrated by having a bunch of magic items and having no idea what they do thanks to lack of luck on their spell craft rolls.

Ironically enough BB Spellcraft simply isn't all that great for a spell caster, there's no identifying a spell that is being cast and Detect Magic tells you the properties of a held item without need of a spellcraft check.

As far as I can tell from the rules, however, Spellcraft does allow non-spell casters (and spell casters who don't have Detect Magic for some reason) to make a check to identify an object. Unlike the normal rules Detect Magic being active is not required.

For a spell caster with the Detect Magic cantrip/orison the only real use for Spellcraft is that it allows you to identify a magic object's properties without holding/touching it. Could be handy for figuring out what that magic pillar on the other side of a river does, or that the statue on the other side of the room is a magic trap that is going to breath fire on you as soon as you step within 15 feet of it.