What's the good of?
What's the good of (doing something)?
What reason is there (to do something); why should one bother (doing something)? What's the good of trying? I just don't have the brains for this class. What's the good of making your bed each morning when you're just going to mess up the sheets again at night?
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
What's the good of something?
What is the point of something?; Why bother with something? What's the good of my going at all if I'll be late? There is no need to get there early. What's the good of that?
See also: good
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.