What I do know is of a non-technical nature. Philips reasoned that people wanted to do word processing, but didn't want an unreliable, hard to use machine like a computer. So the Videowriter is a computer that does one trick only: word processing. You turn it on, you process words, you turn it off again. No programs to start, no DOS, no anything. Great advantage: it is indeed easy to use. Great disadvantage: if you have any other computing task to do, you need a computer on you desk as well. Added disadvantage, due to Philips's stupidity: the diskette drive uses its own format, so no data exchange with a computer is possible. Probably this killed the idea.
I have a little piece of software for MSX computers, that enables those to read Videowriter disks. So for those of you out there that need to convert data, there may be a solution. I'm not going to convert data for you, but the software is right here. An old MSX-II should be easy to come by; it will write your converted data onto 720 kB formatted pc disks if you ask nicely.