The tension on the muscle is the only thing that matters, if you can get the same amount of tension using a lighter weight, you would be stupid for using the heavier weight. Unless of course you consider building your image through strength display a part of your goals.
A lot of good physiques have even been built without extra weight. Meanwhile you see twinks in every gym curling 150 pound barbells and other heroic feets of uselessness as far as hypertrophy is concerned.
Now of course (for people who aren't able to grasp the relativity of this all), some people will have to use some more weight, relatively speaking, to someone else who can generate stronger contractions using less weight.