I'm obviously not the target audience, so I can't understand the use case, PDF seems to be such a useless format for anything other than viewing and perhaps annotating (which it does great at).

Can you explain why anyone would use this assuming I already have a way to export to PDF? zip to PDF sounds strange.

PDF is just a common format used when sharing documents for viewing, like you said. No deeper meaning to it than that.

This tool can convert many file types to PDF without the need for acrobat, office, etc. Basically, this just costs $20 and those cost $200. It's just a small, one trick pony piece of software.

How is this different than say... http://www.dopdf.com/? This is really a crowded space with plenty of free alternatives that are quite easy to use and work flawlessly

Well, DoPDF does look nice. Honestly, it has more features than PDF Everything. I'm not sure how to distinguish mine from theirs yet, or how to make mine worth $20 when theirs is free. Most of those features of DoPDF can be added to PDF Everything quite easily. I just have not added them, yet. Getting those in should help me make a case for PDF Everything.

I would like this as a SaaS - I upload a file, and your service returns a PDF.