I like it because it's not over-engineered with like 10 classes to do a simple dialog. You can go to any .vue file and look how they do it. It's not very difficult to copy some bits of the code and css, to do your own components. They use a bit of mixins and whatnot but for the most part you can reuse some of that code without having to bother with the node packages and whatnot. Plus they have a bunch of useful little bits of js in there for dom manipulation etc.
I also learned how to manually instantiate components and passing props to them, from this codebase. It wasn't made obvious in the Vue docs.. and it's actually SUPER useful when refactoring old codebases (like YUI2).. where I do'nt have the luxury of wrapping everything in a view, I can make a Vue dialog, or a Vue bar chart.. and "mount" it to the page. Then I can use the webpack build, single file components & all the good stuff from a modern Vue build in a legacy web app.