Comment by vanviegen

Their goal is for their target developers not to have to learn html and css. Text and justify make a lot more sense to those whose layouting experience is mostly based on MS Word then span and text_align do.

Also, let's not pretend that html/css is particularly well designed or easy too learn. It's the backwards compatible result of decades of experimentation, where the initial design did not even remotely consider building interactive apps with it.

Modern web app dev requires learning way to much (archaic) stuff, just to create something that ought to be simple. Rio at least seems to be trying hard to address that.