As someone who has spent many years supporting users including desktop backup systems, backup programs that are even slightly 'visible' to them in terms of slow

As someone who has spent many years supporting users including desktop backup systems, backup programs that are even slightly 'visible' to them in terms of slowing down the machine are deeply reviled. Apple's target market is creatives. Lots of audio and video folks. Folks who really, really do not want their computer screwing around making a backup when they're in the middle of trying to get things done.