Prompting users to save web app to homescreen

I've created a web application and have it set up so that if the user launches the web app from the homescreen it will operate similar to a native app.

On the Chrome developer site, they state

Do not prompt the user to add your app to the homescreen.

I cannot find anything related to this with regards to iOS/Safari or Mozilla/Firefox best practices.

Is it bad practice to prompt a user to add your web app to the homescreen even though it might enhance the user's experience?