Functional bikes. Not Porn not Anti

Because they're much more useful for everyday riding, would you ride with two panniers everyday? (unless job required it).

I've rarely ever ridden the Oak without the handlebar bag, not just because a bit of weight improved the handling (it feel overly sensitive without it), but it's always useful to have a bit of space for the usual jacket, puncture repair kit, inner tube etc. and still have enough room for clothes, groceries and the like.

It's kinda like asking why people prefer a saddlebag over two panniers on the rear, it make sense on a day-to-day basis.

Just 'cause I can't leave it...

... for riding in London I would (and do) use a bag. I don't have to ride that far so keeping everything in a bag that's already on my back is more practical.

I do see that bar bags are really useful. They clearly have loads of advantages. But I don't really buy into the whole handling argument. If handling when carrying weight was the main concern you'd go for low-rider ones. People choose bar bags for the other functional options. If you wanted to stack it with weight you'd choose something lower, front or rear.

Obviously it all completely depends on what sort of riding you do.