For CRUD apps, using Rails etc. with Turbolinks[1] is the best way to go IMO. It gives you the SPA feel without the headache. In all SPAs, we load JSON, with Turbolinks, we load HTML of that page alone (without the CSS, JS etc).
so if i have to rewrite my js with this just so i could fake SPA then benefits are so much smaller
Compare this with rewriting your app as an SPA.
https://github.com/turbolinks/turbolinks/blob/master/README....
Turbolink is a crutch for people that are not able to server side render an html in a few milliseconds.
It's fetching and replacing the HTML that needs to be changed, but removes the need to do a full-page reload, so the browser doesn't have to re-load and re-parse all of the HTML, and JS, and CSS. Even though the browser will keep a lot of this stuff cached, Turbolinks can make a site feel a lot faster from a user's perspective. But regardless, it's more than just a loading bar at the top of the screen.
Whether it's the right fit or not depends a lot on what you're trying to do.