I think all depends on who is looking at them. First, a JW who is not even interested won't be on the internet looking for this type of information. But to those JWs who have questions, maybe someone said something to them in the past, maybe out in field service. Or there is just something that keeps nagging them at the back of their mind but is way too afraid of what would happen to them if they asked someone in the congregation. Also for those who have left or on their way out; sites like these can be very effective. If anything just having the information out there, and the proof to back it up, is extremely helpful.
When I had some doubts, and I won't go into the details, but the anti-JW sites that I found had information using the Watchtowers own publications. The sites told me which book, which page(s), and exactly where I could find the information (and I doubled checked with the publications I had) I needed to confirm what was digging at me from within the organization. At the time I had books dating from back to the early 1950s. It's not that I have lived that long, it was just older witnesses had given me those books from that time period.
I remember after I had discovered that I had been lied to, my first reaction was to throw everything away, and I did, a decision that I regret to even this day. Looking back, what I wished I had done was to give those books to someone who could put proper use to them, but I didn't.