Because it aids the repair and growth of body tissues, vitamin A is crucially important to bodybuilders, but also vital for the general population. Other important functions of vitamin A are the development of the reproductive system, skin, eye sight integrity. Many bodybuilders probably have marginally low vitamin A intakes due to higher levels of activity/muscle growth/repair and could benefit from consuming extra plant-based sources of Vitamin A.
Another dietary issue that vegans don't have to worry about though is Vitamin A overdose, and here's why. Plants contain beta-carotene, which is a precursor to Vitamin A, but not actual Vitamin A. The human body is capable of selectively converting beta-carotene to Vitamin A only when it's required. When the body currently has enough Vitamin A, the conversion of beta-carotene slows down to make sure there isn't a excess of Vitamin A, which is very harmful.
However animal sources of Vitamin A are known as retinoids. The body doesn't have a safety valve for turning off the absorbion of retinoids - they are always absorbed no matter what - which means overdosing is possible. Too much Vitamin A (3 or 4 times the RDA) is very harmful and can be fatal. Prolonged (slight) excess of Vitamin A from animal products is associated with the following symptoms: nausea, blurred vision, fatigue, weight-loss and menstrual abnormalities.
Excess Vitamin A has also been suspected to be a significant contributor to osteoporosis. Excess Vitamin A during early pregnancy has also been associated with a significant increase in birth defects. These defects may be severe, even life-threatening. Even twice the daily recommended amount can cause severe birth defects. The FDA currently recommends that pregnant women get their vitamin A from plants (beta-carotene), not animal sources.
And remember, overdosing on vitamin A is only possible when consuming animal sources, so vegans don't need to worry about that!