I prefer writing in Latex more than Word, but it still isn't a happy experience for me. The errors are nearly useless, I'm constantly compiling and waiting for pdf output, and then I have a static pdf as output, which isn't so exciting.
That's why we decided to try and build something different. I want to look at rendered text most of the time during my workflow, but I don't want to use Word. I'd prefer a markup language with a nice-looking, easy to remember, syntax, which is why we offer Markdown. Collaboration should be easy, which is why it's online. I want things to be dynamic, which is why we're working on that. I want to share my data with my figures and my analysis with my data. Again, we're working on that.
It is true that in 2013 what is important is publishing in respected peer-reviewed journals. But we're really trying to think about what an article is going to look like in 2023. I highly doubt it is going to be a static pdf (or static html version of said pdf) available only to paying users of a respected journal, or users whose institutions are nice enough to pay for them.
I'll be the first to admit that we have a long way to go, but we gotta start somewhere.
Some entities like ScholarOne/Cambridge Journals wants you to individually upload your images and your text separately. Since a user is just writing their paper on Authorea, maybe, you can keep track of what journals they are aiming for and reformat the publication for multiple journals in ONE SHOT. That'd be the biggest time saver ever.
At the end, doing research is fun but publishing is a painful process, and you are judged based on publications. Reduce the pain.