Done right yes, it will feel a bit snappier, and you can integrate offline support without a huge amount of extra complexity on top of your SPA.
Sadly the trade-off currently is that your frontend is going to be far more complex to build than if you just rendered some HTML from Rails. You end up needing to duplicate your model layer in the frontend, debugging is harder because now the bugs are on the client side, which you have no access to after the fact, and integration testing becomes a very real challenge.
These are all surmountable problems, but they're not trivial, and in my opinion they're not worth it for a few hundred ms of response time, especially when you can get close to the speed ups offered with some judicious use of caching, Turbolinks, and a thin layer of JavaScript in the places it makes most sense.
Sadly the trade-off currently is that your frontend is going to be far more complex to build than if you just rendered some HTML from Rails. You end up needing to duplicate your model layer in the frontend, debugging is harder because now the bugs are on the client side, which you have no access to after the fact, and integration testing becomes a very real challenge.
These are all surmountable problems, but they're not trivial, and in my opinion they're not worth it for a few hundred ms of response time, especially when you can get close to the speed ups offered with some judicious use of caching, Turbolinks, and a thin layer of JavaScript in the places it makes most sense.