[svalorzen]

The benefit is indirect rather than direct, as in the user benefits from the increased availability of plugins/guis since they would be easier to create. Also vim lacks lots of very simple but essential features of modern code editors simply because it lacks the graphical capabilities to do so (an example would be displaying the documentation of some method you are autocompleting, something which I have never seen in vim and which I actually believe is impossible).

[psquid]

> an example would be displaying the documentation of some method you are autocompleting, something which I have never seen in vim and which I actually believe is impossible

For python at least, having 'preview' as part of your completeopt has it display the docstring of what you're completing. And :h completeopt suggests that's intended behaviour for all types of completion (where it makes sense), too.

[fmoralesc]

Yes, but currently retrieving that info is done synchronously, so it might slow down things. Under neovim's model, this can be done more efficiently.