Yes i can confirm Favicons and ServiceWorker components are enough for PWA.

Development of this component has been discontinued because it is no longer required to install a PWA.
Browsers like Chrome and Edge meanwhile have their own built-in installation routines and only need the Favicons and ServiceWorker components. In opposite, Firefox has dropped PWA support for PCs now, thus even the SiteappInstaller would be of no help anymore.

Added Korean langauge

‐-----------------------------------------------------------------------------------------
(UPDATE - MONDAY, MAY 24, 2021)
The Site App Installer is PERFECT.
To enhance the experience for your users, additionally install the Softlab24 "Auto Login" component.
(Trust me, you will be so glad you did. It is a perfect compliment to the "Site App Installer" component).
The "Auto Login" component adds a convenience factor to your site's users that they will appreciate and keep them coming back to your site.
https://www.softlab24.com/product/view/1692/auto-login
This allows users to simply click your site app icon, and thus go directly into the site.
These two components work together in perfect harmony.
Bravo!!!

I don't know much about PWA as Z-Man do but if it supports cookie long term , you may use Remember me component for your network

I really love the site app installer. The PWA works excellent. The only thing is I wish there was a way to keep the user logged in, instead of always having to sign in upon every visit.
Is this possible?
The PWA works so well in both iOS and Android. Users have the full site experience, can even play the shared videos in users posts. Everything is there, and it just works.
This component truly shines. Maintains the entire look and feel of your OSSN site. (Logos, theme, etc.)
This is so much better than the mobile app, which is extremely limited in functionality. I really think someone needs to change the awful "home" icon in the mobile app, not to mention all the generic "Social Network" branding of the mobile app. (I do understand its a shared app, but the complete generic nature of it is too much and confusing to users. Remember, the users are there to share post and the like... most of my site users are older people who just want to share a special moment, picture, video etc. They don't even like logging in, let alone enter in the domain credentials into a strange "Social Network" app with an unfamiliar icon or logo).
If this component could implement a stored login... it is worth MORE to me than the current mobile app. (Yes, I would definately pay for such functionality)!!!
This component is EXCELLENT!!!
In fact, this could easily be a premium feature and remove that terrible current mobile app.

any updates on this

According to
https://developers.google.com/web/updates/2015/12/getting-started-pwa
a site must have been visited at least twice.
So maybe that's the reason it wasn't working for you immediately...

Unfortunately, the pwa specs are not 100% clear, hence leaving enough details to be implemented this or that way in different browsers.

So, for no apparent reason, (as I have not attempted to click the green button in a few days), as I launch Samsung internet this evening a notice pops up asking if I want to install an app and it has my site name associated.
I allowed and it installed remaining my saved information for login. It didn't install as a homescreen shortcut, but as an app and can be found in the app listing. Anyone know how this may have happened??
While I am somewhat confused, I am glad that it worked, would love to reproduce (nothing for Chrome yet) for users.
All features seem to work.

Thanks for the info Z.
Update on Firefox.
It only works if I am logged in on the browser before launching pwa.