If you are a partner in the restaurant, then sure, go for it. If you are self employed, then go for it.
Basically, if you are doing sales you need business cards.
But if you are the Chef of a busy restaurant, (ie "production" not sales) business cards are a p.i.t.a..
If you hand them out to people, they will stay in a pocket until the garment gets cleaned.
If people ask for them,75% will want to sell you something (insurance, cars,...