Second Chance pretty well covered it and told you most of the reasons why.
I own;
.204 (40gr V-max) Wanted the latest & greatest - use it when I'm making stands
.223 (55gr V-max) AR platform - use as a walking stick with a one point sling
.243 (75gr V-max) First predator gun I brought - doubles as my small deer gun
Kill coyotes with all of them.