If you want to understand samādhi correctly in the Buddhist sense, you must see it as it is described in the scriptures, as the mind that is malleable, fit for work. The mind that is malleable is one that is ready for work, in that it is firm and still, as I've just explained with the comparison of holding an object still in order to see it clearly. This means we use samādhi to facilitate the arising of wisdom.
Wisdom is of many types and can arise in many ways. For instance, in our everyday lives there are countless things demanding our attention and consideration, but if our minds are not calm we don't see them clearly. At some later time, having calmed the mind, these things may arise once more into consciousness, so that we can review them more clearly. This is one type of wisdom which can be derived from samādhi: seeing the events or experiences of our lives more clearly in retrospect. Cases where wisdom was initially not apparent become clearer.
In addition to this one can also use samādhi as a tool for looking at experiences as they arise in the present moment. For example, a meditator practices samādhi to the level of jhāna, then proceeds to examine the various qualities of jhāna -- vitakka, vicāra, pīti, sukha and ekaggatā1, bringing them up for scrutiny so as to see their true nature, as impermanent, stressful and not self. This is a function of wisdom.
Wisdom can thus be used to examine an event from the past or to examine experiences in the present. In either case, the result is the same, that of seeing things as they really are.