A PWA can be a good supplement to an existing application, but only in certain contexts could it fully replace.
We (mostly my colleague) implemented one for a mapping application that was previously browser based online-only.
It allowed you to download what you saw on screen, +/- a series of zoom levels. It also brought a lite functionality of the main app over.
People were using it for reference when they went out into the field. We had people adding it to their homescreen, as it was more accessible to them that way, but we had to have a little guide on how to do so.
Most of our users are older folk in government posts, so stuff like that needs a help guide in our context.
