Devlopement is easy and no need to learn different templating language for a front end devloper to develop the web pages like PHP, JSP or django templating
Required data on page is served through JSON API from server not using context variables
Switching into multiple URLs in the web page is easier and faster since routing is on clinet side
Since all static content like CSS/JS has been loaded initially so redundancy of static variables minimizes the server load
Using the same API the mobile application can be simultaneously build reducing the load of back end devloper.In this way a back end devloper can concentrate over business logic and code optimzation instead working on page rendering stuff of fron end.
The devlopement would be fast as the front end and mobile developer can build their application using dummy api’s and later integrating them.
Example of SPAs : gmail, Facebook, Twitter
Web app speed is slow as each routing requires a call towards server whihc may take additional round trip towrads server.
SEO is better managed in MPA
Backend devloper need to create mobile APIs to give JSON data to mobile devlopers(redundancy of logic).
Tightly coupled front end /backend
As per the given approach it seems to be use SPA for a better user experience and fast devlopment process.