PhantomJS enabled us at the time to bootstrap a big project at work where at the end workflow the app had to turn HTML orders to PDF on the fly, eventually we moved to WKHTMLTOPDF (https://wkhtmltopdf.org/) which is much less hungry with resources but nonetheless PhantomJS played a huge role during the early days of the project and was easy to setup. If I remember correctly the only down side was to find the correct format for our HTML template so PhantomJS would render proper page break and repeat the header for super long orders.

I can understand why stepping down is the right decision, maintaining such project by himself is an amazing feat on its own and even more when it proves to be useful for so many companies. Sadly when it becomes your second job you might always be on the lookout for a clean exit and such opportunity just became a reality.

Good luck in your future projects Vitaly!