Difference between msiexec /qb and msiexec /qb-

Difference between msiexec /qb and msiexec /qb-.
/q - This means there can be or can not to be some interface change. Frequently there is another parameter set to /q switch.
b - now it will happen basic user interface process
- means no modal dialog boxes, that means if something goes wrong and installer want to tell you that, then dash parameter at the end means "shut the mouth and do not tell anything, do not pop up any windows. I don't wanna to distract any users to press some kind of OK button. Are we clear?"