I brew Hefe for one reason: to drink at the pool. Therefore even if I kegged I would end up bottling most if to take poolside anyway. I keg and force carb pretty much everything, but I think Hefes are a good candidate for natural carbonation for 3 reasons:
1) There is a ton of yeast left in suspension and they seem to carbonate full within like a week.
2) If they are kegged you have to shake the keg from time to time to make sure you have enough yeast in suspension. With bottle conditioning you always have the right amount of yeast in each bottle.
3) I don't have a regulator for each keg in my kegerator. This means all of them have to be kept at the same carbonation level. A Weizen should be highly carbed, far more carbonation than I want on my other kegs.