A muse may be used as a starting point for creative work, but may also provide a support around which the work might develop. The work might be about the muse, but often the work provides the frame around which the work develops, rather like the supporting structure in an espaliered fruit tree. The support shapes the work, but does not provide the tree. That is the function of the tree.
One of my favourite examples in history is Charles Dodgson's muse, Alice Liddell. Alice provided the framework for the quite remarkable weaving of philosophical conundrums and mathematical concepts which otherwise would have been well out of the reach of many adulds, let alone the many children who enjoy the Alice volumes. It would seem just one golden afternoon on July 4th, 1862 spent in the presence of his muse was sufficient to trigger a cascade of imaginative writing from the Oxford mathematician. This is not typical of his normal writing, quite unlike such works as "A New Theory of Parallels", a treatise about Euclidean geometry.
Dodgson's friendship with Liddell is subject to some speculation. The use of a muse need not be so close or even first hand, and this is reflected in my use of Marilyn Monroe. I have not met her, am not likely to in this part of the multiverse, and I cannot even claim to possess much knowledge of her life or art. Sometimes I will catch a snippet of information which acts as the start of a poem and sometimes the poem already exists in some form and the little knowledge I have provides a discipline and form to the work. Occasionally the concept of Marilyn intrudes into the work, sometimes intentionally and sometimes not, perhaps because the concept has proved useful and old habits are hard to be rid of and perhaps because I have come across another article involving Marilyn that is sitting in the back of my thoughts.
Although I do not have a good understanding of how a muse functions, I am still happy to use a muse, knowing I am surrounded in other artists who use the same mechanism to provide great work. I am certainly not going to ignore a tool with such a great pedigree.