Adding new code to Rails controllers can bring a couple of problems with it. Sometimes controller actions get really big, and they tend to do a lot of things. Another common problem is an increase in data over time, which can lead to slow page loading time. Adding new code to controller actions can also sometimes block the rendering of some actions if it fails, breaking user experience and user hapiness.
After some time, we saw that this can be extracted to render_async, a gem that speeds up Rails pages for you - it loads content to your HTML asynchrounously by making an AJAX call to your Rails server.