Because when this bug happens, the pilot is going to face a "christmas tree" of warning lights and cautions, most likely provoking an immediate PAN or Mayday and a possible diversion to the nearest suitable airport.

Loss of attitude info is a serious business, in the worst case the pilot may be left to fly only "raw data" and using the backup "steam gauge" instruments, because the displays and automation will stop working. Such event is no cake on a big jet, even during daylight, perfect weather and with the crew perfectly current and capable to fly like that.

Murphy will have it that it happens during night, in a storm and most crews today are trained to rely on the automation and rarely getting to hand fly, even less raw data, without any of the computers. The result will be another AF443 ...