When using desktop based accounting, files can become corrupt and ongoing backups are always needed.  

You also have to exchange files with accountants, causing even more freezing and disconnect.  Quick and efficient analysis are delayed until bookkeepers can key type in all the needed data. Not to mention, human labor has become more expensive than machine learning and imported data. 

With all of this in mind, it's easy to see that in today's fast paced need for data, reporting and decision making can't wait for bookkeeping.