You don't create fancy professional documents without printing them... and if you need a printer, then you're probably at the office, so you probably already have all your regular tools.
If you are going to do anything on a regular basis (quote, contract, sales letter, etc) you already have a template of it in Word or whatever... and it's private.
You explained the features pretty well, but what's in it for me?
The problem with Word or Libre Office is that once you've fight several long ours to make you layout or template perfect, there is always something not quite right. And when you're writing, you have to select the text where you want to change the styles on.
Using Markdown or Textile (with an already made CSS) makes it really easy to just write, hit a button and BANG, document is there, ready to be emailed.
Plus I see this process (easy Markdown editor) to be very usable with tablet devices.
But maybe we are wrong, this is why we were asking here ;)
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