"I came across someone's blog where he wrote about serving his Javascript game via web and via an app that can be downloaded on Android phones."

So a blog you found is the authoritative answer on the subject? Both (the fact you found a blog/the claim of an app getting more users than a website) simply sounds like a matter of marketing. Regardless of how you deliver it, you're attempting to deliver a service. I'd focus my efforts there.

No, it wasn't due to the blog. I had already started on the PhoneGap thing before I chanced upon it. The app that I will be making is the sort that people would not normally google for and use via a phone's browser.

A Javascript game - or application - is already running in the device. Converting it to an actual Android App is not a structural change. (Don't know about conversion to an iOS app.)

Converting a server-based application to an Android app, however, is a serious structural change. And you may still end up with an app that communicates with a server. (And probably even more difficult to do for iOS.)

A more realistic approach would likely be converting just the web-based UI to an Android (or iOS) app.

Also, I've heard that there are apps that, supposedly, just pass an URL to the web browser. I haven't tried. So far, the only Android app I've "created" was the result of following a tutorial and adding/modifying some features. Curiosity satisfied, I've not had a reason to do more.

I'd much rather use Perl. Then, if I need to use it on my tablet, put a web interface on it. If some one else needs to use it from their tablet or smart phone, they will, despite the lack of an app.