Advantages: They look better, are lighter, and won't stain tannic wood.
Disadvantages: They can't produce quite as much force as a bar clamp. They are not as readily available.
The amount of force, wear, and stiffness will depend on the specifics. I have some wooden bar clamps that are stiffer than pipe clamps and competitive with some steel ones. But they're big, and they operate with wedges rather than screws. I have made a screwbox intending to make some bar clamps similar to these.
If you go by the dictum that you can never have too many clamps, they are always useful as more clamps. As you use them, you will likely find situations where they are preferred.