Answer:
A spoon or any device will "mix ingredients together." A wisk preforms a very important additional function -- it incorporates larger amounts of air into the item(s) being mixed. An example is working with egg whites. If you use a whisk you will incorporate air into the egg whites and they will turn white and will increase in volume drastically! A spoon on the other hand would just more or less move the egg whites around in the bowl. The "electric" form of a whisk is the whipping attachment on an electric mixer, however, if your arms/wrists can handle it, whisking will provide greater results.