I personally got it just so that no one else in my company would ever need to do so; there are stupid companies which won't buy a product without integration, and where they have artificial requirements for integrators being certified. Given that it is only 1% of useless pain to enable 99% useful rewarding stuff, I found the sacrifice worthwhile.
But to be clear: I believe pretty firmly that for technical / software security, the CISSP is useless.
I'm not sure how I feel about SANS/GIAC. Absurdly expensive IMO, but potentially actually has some value for sysadmins doing system security. I can't think of what CISSP is actually good for, except maybe trivial pursuit - crappy consultant edition.
I'm under no illusions about the certification's marketplace value and I doubt I would have ever paid for the course/cert on my own, but it felt like one of the better formal trainings I've been through in my professional career (which, granted, isn't saying a whole lot by itself).
Also, the certificate comes mounted on a comically oversized plaque, which provides some entertainment value.