I can see that semi-frequent fliers could find consistent lettering helpful. When they ask for particular seats at check in they can see from the BPs whether they have what they asked for - without waiting to get to the plane for a nasty surprise. I wish there were consistency in seat row numbers. I have been caught out a number of times with Asian carriers which can have the front cabin numbered 11, 12, 13 and then the rear cabin 21, 22, 23...