> Stuff like forms, invoices, flyers, handouts, leaflets, business cards -- an afterthought, at best.

It is because you can typeset beautiful long text algorithmically and all these small forms like invoices and flyers are more graphical design than typesetting: you need to place many small elements precisely, not relative to each other but to the edges of the page / optical centers / etc. It is not very convenient without WYSIWYG. Possible, yes, but will require many trial-and-error when in WYSIWYG layout program can be done from first try.

Think about tabloids too: text, which wraps around non-rectangualr images, cut-outs, etc. Hard to do without seeing what you do, only with text and coordinates.

Edit: typo test → text.