i think that if you do a fair bit of riding on the road then bar ends make sense, if only on a saftey option.
the reason why i say that is a few times i have had people open car doors on me when i have been riding past them. the worst was when i was doing about 28-30mph going down a hill, clipped a car door that was just being opened. the car door hit my bar end, and sent me spilling down a busy main road. and i swear, if i didnt have the bar ends then i would have lost my little finger. i chipped a bit of bone out of my forearm and had lots of brusing all over.
since that happened i would not have a bike without them.