I guess I just got a different read of it than some of y'all...
I've read all of both volumes of "Play Dirty" and what I got out of his stuff overall was some ideas on how to make my games more engaging and entertaining...and players LOVE it. I wish I could find the article on the "Die-Hard Effect", it's in I think the original 7th Sea GM's Guide and maybe in one of the Play Dirty books (Don't have my copies to hand).
The basic idea is that players love a challenge, love to feel like they WORKED to earn their victories and their stories. You don't have to kill players, and only rarely should, it's a lot more interesting to drag them through the mud, the blood, the sweat and the tears...because when they finally emerge victorious they feel pretty **** awesome. part of that article series talks about the final trial of the MR. Carter...everyone who ever played in that campaign showed up and the payout for everyone was worth all of that time spent trying figure out who was behind everything...and in the end they did it like heroes.
Sure you can play the 4-color cookie-cutter heroes saving the city from bad guys on daily basis...but that gets kind of stale after awhile.
Now add some depth to the characters, look at and expose their flaws...and their strengths and you get a much better, much more involved story. And if you look at any of the long-running stories you'll see that kind of thing happen over and over again...Peter Parker losing Uncle Ben motivates him to become a Super-Hero, Tony Stark's Alcoholism, Steve Rogers do-good nature etc...
In the end you get out of a game what you put into it...if the GM and/or Players want to do 4-color do-gooders, more power to you, but that should be part of the pre-game discussion to set the expectations. If they want more engaging stories, stories that hit them in the feels...then they should all agree to it.
Play Dirty isn't for everyone, and you don't have to like or use any or all of it, but the general idea is to get some new perspectives and maybe some ideas to bring more depth and engagement to people's campaigns.
*I* Enjoyed both books and did get some interesting and useful tips that have made my campaigns and characters more interesting in the long run.