Answer
The magnitude of K in this case represents that the concentration of products will be very large compared to the concentration of reactants. Therefore, it is a good reaction for a source of products.
Work Step by Step
Looking at the K expression:
$$K = \frac{[Products]}{[Reactants]}$$
When the equivalent value of a fraction is large, the numerator is much bigger than the denominator. Therefore [Products] >>> [Reactants].