Presumably they're referring to the ability to parameterize the target page size. In that case, absolute coordinates don't work well (if at all).

Parameterize! That's a new word I didn't know. It adequately describes how I typeset my books, and I must not be alone. The ability to tell LaTeX to drop a picture around here, to the best of its ability, with the possibility of moving it down a paragraph or two if it doesn't fit is vital for me.

I think that's a missing feature of Typst yes, to have figures be either "here" or "top next page" automatically, with that priority. It can't do that. The confusing part was that this has nothing to do with the images of this coffee stain package, because they are foreground/background and can be placed freely on the page (any corner or any custom offset from any corner; i.e from top left corner you can use page coordinates).

The coffee stains overlay/underlay text, so no layout problems at all.

But the dx/dy arguments also take percentages besides absolut lengths. I still don't get what the the other poster means by that fundamental limitation. I think they're confused about absolute positioning of background images vs floating figures. But typst has the analog setting of `[htbp]`, so the same "fire and forget" workflow is possible.