The difference is that this editor will supposedly not even allow the code to be in a state of type errors. You literally can not construct a program that is not well-typed. Don't ask me how that editing experience is supposed to work, or if it's a good idea.
Actually, that sounds terrible. I already am sometimes annoyed when I try to first use a variable, and then go back and decide where should I declare it - visual studio doesn't like that - literally not being able to go through a broken state would be annoying.
If this video < http://pchiusano.github.io/2015-03-17/unison-update5.html > is an example of this, then yes, it does look annoying and inefficient. Now I'm not sure if I understand exactly what he's doing here, but it looks like something along those lines: rather than inputting what he wants directly via the keyboard, he has to choose a pattern (like variable-operator-variable) from a drop-down list, and then tab between the fields to fill in the pattern.
A poor analogy might be the difference between speaking words verbally to form a sentence vs. shuffling through a stack of index cards to find the right words to arrange on a table to form a sentence. The latter would be useful if you were just learning a language, but once you know how to speak it, that would be an enormous waste of time.
I'm annoyed just by simple error-messages (like in Eclipse) while I'm editing in a "broke" state. I know that this class isn't valid Java yet, Eclipse; shut up! :)
