I do think a heavier racket is better for responding to the shots of a 5.0 or better player, talking a strong hitter.
BUT, since I'm a 4.0, I don't need to focus my returns based solely on strong hitters hitting into my court.
While YOU may be a 5.5 playing 22 year old Div1 singles players, I only see that ball maybe twice a year, max.
So what ball do I face the other 95% of my tennis? A slow moving 4.0 sitter ball. For that, I need a 12.5 oz racket?