Oh fer Pete’s sake.
It’s a promotional blurb for the book on a promotional website for the works of St Alphonsus - doubtless they sell that book on the site, no? What are they going to say, that it’s obscure and has influenced few people and that’s why you should read it or buy it?
Of COURSE it’s going to say he’s influenced millions. Just like EVERY published book, regardless of its quality, has fantastic-sounding blurbs and introductions according to which they’re every last one of them sublime and universe-changing and going to influence millions.
And if you fall for any of them then I’ve got a nice statue in New York Harbour I’d like to sell you …
Blurbs and introductions exaggerate for effect, it’s just what they do. Particularly when they’re from people specifically trying to sell or promote what they’re writing about!
Like I said, there’s only one way to find out for sure. Put your money where your allegedly truth-seeking mouth is, and go to the source. Visit any Catholic Church any Sunday and ask the people there, you’ll see for yourself just how few have even heard of it, well fewer still have actually read it.