True. I was fortunate to find it 15 years ago, when the mod_perl list was very active, hence got a lot of guidance, and there are a few gotchas. Now that I'm replying to you, I recall that I did have to study this book before I could be operational.

However I found the effort was worth it because you can do so much with mod_perl (I build web based applications for a living, the hooks to the Apache response phases are awesome); and you get to write perl code, not cgi code. Also, very efficient.
Anyhow, you are right, not for someone who is building a hobby site. But if one wants to make a serious one, it's a great tool.