Grr, I thought this was a thread about how to delete them, but you apparently want to leave them in!
Seriously, what are they there for. I always lock the car electrically with my key, I even set it up so it cannot be locked without the key. I always unlock the car electrically with my key, but if I wanted to unlock it via the knobs I couldn't because I wouldn't be inside. If I'm inside, I unlock it by the "unlock all" button or by pulling a door handle twice. I can't think of a single circumstance where I would use the knob.
Meanwhile, the knob on the driver's door is located where it digs into my upper arm whenever I try to use a keycard, pay a toll or get a toll ticket, or get drive thru.