Fair enough - but in some editors (acrobat?) you can embed the fonts you need to avoid this problem.
The problem with bitmap versions is if you want good quality printable versions of multipage documents they will get very large.
-Carol Haynes
The real issue is to be sure that the PDF will be the exact copy of the original Word document. When there are many pages all with a lot of mathematical formulas, spotting manually an error due to a font or whatever other reason in a text structured PDF is virtually impossible. Granted, the size of created files could be an issue, but it appears more manageable than random errors that would slip through.
BTW, I tried PDF Image Printer and it's exactly what I want. Except for the price tag...