With SPAs, site visitors find everything in one page. It loads once and everything is there already.
Loading an additional page, can rather strain the flow you may already have established between your site visitors attention and the content, info and functions you provide.
With the help of a SPA, you can avoid interrupting the user experience by re-setting the scene with a new page, time-consuming interactions with the server which can invite to drop attention and switch elsewhere.
With the assistance of a SPA, you can keep away from tedious communications with the worker. It gives further developed page execution and offers greater security as far as information assurance.
Bottom line, an SPA is an application that works within one single browser page and does not switch to another page. Some of the example applications are GMail, GitHub, GMaps, or Facebook.
Keep the experience flow of your visitor at its high.