- Create a Word/Excel using OOXML does not load pre-installed add-ins because OOXML just creates a text file (XML). Even if a pre-installed add-in is to crash, you can safely create a Word/Excel using OOXML.
- PIA offers properly structured building blocks of Excel/Word. If you combine building blocks of PIA in an incorrect structure, you can notice your mistake at a build time. In contrast, OOXML only offers building blocks of Excel/Word with no structure. Using OOXML, you never know at a build time whether building blocks you are combining is in the proper structure.