Don’t know how difficult it could be but having A2HS (https://developer.mozilla.org/en-US/Apps/Progressive/Add_to_home_screen) could be a nice to have functionality.
Requirements are :
To be served over HTTPs
To have a manifest file with the correct fields filled in.
To have an appropriate icon available for displaying on the Home screen.
Chrome additionally requires the app to have a service worker registered (e.g. so it can function when offline).
What do you think about it?