Bodybuilding isn’t about lifting heavy, but lifting to failure is easier with heavier weights.
You have to lift heavy to increase strength beyond your natural limit.
But for muscle mass and appearance, light weights are good. And injury rare.
I’ve been lifting light lately, mostly of necessity. I have no spotter in my home gym and am 65yrs old now.
4 x 10 75lbs bench press and dead lifts.
Slow. Always slow, focusing on precise form.
And 5 x 10 45lbs barbell curls, rows etc.
It works.
I’m strong and muscular for a 65yr old man.