My understanding (which is my recollections of a dive into typewriter history decades ago) is that avoiding typebar collisions was a real concern, but that the

My understanding (which is my recollections of a dive into typewriter history decades ago) is that avoiding typebar collisions was a real concern, but that the general consensus was that the exact final layout was strongly influenced by allowing salesmen to quickly type out 'typewriter' on the top row of letters.