Yes and no, that's just my opinion. You're right that the Sun is more powerful in regards of this matter such as wealth and overall it's power over Venus.
But then again you have to take in consideration one's astrological natal chart and if someone has better connection with Venus in his chart and see when there's a good transit and progression going on and so on so forth then Venus might be more beneficial then the Sun Square , especially if the Sun is shadowed by other planets , let's say you might have a weak Sun but a strong Venus, point is that : Venus square could be more beneficial. No matter what , I would use Venus only to attract love and to improve my beauty such as physical one and astral and overall the mental one.