Because the dynamo team refuses to give us converters for that object type. I’m not sure the reason either but it’s frustrating as heck because giving us wrappers would also enable background documents to work better.
Here’s a cool discussion on this conversion process with the author of the orchid package. Essentially he took some ideas and made a bunch of sweet converters for us all to use. This resulted in greater compatibility between our Dynamo packages, which is awesome.