As to why keyboards are staggered in the first place, it is because a staggered layout allowed typewriters to have straight levers to the type guide (where they

As to why keyboards are staggered in the first place, it is because a staggered layout allowed typewriters to have straight levers to the type guide (where they hammer down onto the paper). By having a straight vertical slice for each key, this meant that keys would not get easily jammed. Obviously electronic keyboards do not require this same constraint, but tradition is difficult to change.