Plato is right.
If you're able to produce a truth, that is better than producing an approximation of the truth.
That doesn't mean that the representation might not be useful in certain situations, but if you have the whole truth, then that is better overall.
In the case of virtue, Plato argues that people who act immorally are simply ignorant - if we know how we should act then we will do so. Here again, the whole truth is better than an approximation or representation. There are always elements of a representation which do not fully match that which is represented, and so that virtue, in representation form, would be incomplete, imperfect, and therefore less virtuous.
Plato says it's better to give birth to true virtue rather than to give birth to images of virtue.
Isn't it better to give birth to a representation?