An evenings test on creating materials using Midjourney and Substance Sampler.
The Materials took about an hour each - this being: trying out prompts, creating in Sampler, assembling and minor editing if required in Designer, and renders in Marmoset.
While these are by no means perfect, they are fast! And unique in terms of the image used.
I think there is a limit to using bitmaps this way for sure, but as AI programs get better it may become more viable (still keen to try out DALL-E2 with this method as well).
Next tests will likely be more Designer based materials with supplement grunges and patterns from Midjourney.