One of the reasons would be, if PDR13 could output a video as an image sequence (for example, after compiling a project that is 1000 frames long, can it produce an output of 1000 PNG files (in order, as separate frames)).
I am currently using Sony's Vegas Movie Studio, as it does this - but of course, it would add to PowerDirector's competitiveness in the area if it was possible (or added in the future... hmm perhaps I'll submit this as a suggestion if it is not).
Thanks