In particular, this stems from the observation that many, many programs have an initialization phase where they may read config, open logs, hit the network for

In particular, this stems from the observation that many, many programs have an initialization phase where they may read config, open logs, hit the network for config and peers, etc., and do all sorts of things that they do not do during their steady state operation. However, when programs are "hacked", particularly remotely over the network, they are in their steady-state phase. So while there is in some sense not much theoretical gain to pledge(), in practice it is applicable to a wide variety of software where the program itself can say "Alright, I'm out of my init phase, now crank the screws down on me and make sure I don't do these other things because it's guaranteed they're bad."