It is frequently objected that explanations in terms of the divine will are useless because they can "explain" everything.
One might equally object to quantum mechanics that it can explain any coherent macroscopic state, since all macroscopic outcomes have non-zero probability. This would be a poor objection. For while it could be that any macroscopic state can be given a statistical explanation, these explanations are not all equally good. The statistical explanation of why the cream spreads throughout the coffee is much better than the statistical explanation, invoking flukish probabilities, of why the cream coagulates into a regular nonagon.
Similarly, one might object to ordinary agential explanations. After all, just about anything within the power of humans can be given an agential explanation simply by positing some odd set of motivations. But some of these agential explanations will be better than others.
So it seems to be in the case of divine will explanations. Some are much more plausible than others. The explanation that there is life because God was so impressed with the value of life that he willed there to be life is much better than the explanation that there are platupuses in order to make us laugh. Why is the former a better explanation? One reason is that life is a greater value than laughter. Another is that while there being life is the only way to get the value of life, there being platypuses is not the only, and not the best (giving P.G. Wodehouse his sense of humor and writing ability is an even better way), way to get the value of laughter.
Moreover, notice that just about anything that occurs in a book could be explained by positing some motives or other on the part of the writer. But the explanation is better when these motives cohere well with the motives apparently exhibited elsewhere in the book. Nature throughout seems to exhibit a motive to give reality a mathematical structure and predictability. Explanations in terms of that motive are thus much better than explanations in terms of a one-off motive. In this way, good science, by discovering such structure, will actually help provide very good theistic explanations.
That said, the less good explanations are still explanations. In a typical case where something realizes a value (there may be some exceptions, say if there is some deontic prohibition in the vicinity), this realization of the value will give God a reason to make the case come about, and God will not ignore that value. He will act at least in part on it. So it is true that the platypus exists in part to make us laugh. But a much better explanation will be given by attending to the evolutionary processes that produced it.