Lets assume that you decide to use Str as your main attack.
you have the option of going majority str, even build or max str.
Most players use even build for defense and visual deterrence. That means you either decide to choose an avatar that help you with % boost to both str and int evenly so that you get that additional defense help OR you pick that pure str bonus avatar
That will help you ATTACK and win the most $$ and defend the most against Str. ie: the attribute that MOST PLAYERS USE.
Once you get past a certain tier of stats, your rarely attacked. That's the truth so don't have to worry about defense that much.