I recently built a small three 'page' game for a trade-show booth. By using Ember, I was able to: try out a new CSS framework based on flexbox, save data to localstorage, capture images from the webcam, have 'data binding' of variables so that they updated on the page when I changed them, and deploy to surge.sh in the first hour.

All-told, it took 20 hours, 7 of which was me getting used to the intricacies of developing a full-screen "App" (no scrolling) with flexbox and implementing the designs. I'm good with vanilla JS, but there's no way I could have done all of the coding (three 'game' pages, three 'admin' pages) in less than two days.

I guess the point is, a framework that you know and are familiar with can halve the time you spend on a project. I find that to be especially true with Ember because of the CLI tools and all of the various addons.

Yes, they are very powerful and flexible. These frameworks actually payoff and simplify once your project grows beyond a particular size.

> once your project grows beyond

"Premature optimization is the root of all evil."

- Donald Knuth