In a word, this s.
First, the DMG files are not recognized by all Mac browsers as
Secondly, they decompress and mount on a "temporary" drive. Most new
users have no concept of a "drive", much less a temporary one.
Lastly, the contents have to be moved from the decompressed location
otherwise they disappear on next boot. I don't know how many customers
I have had to deal with that have dragged the app from the temp drive
to the dock.
For a company that prides itself in marketing its computers as "easy
to use", this whole DMG ...