Why would you? To get $10 and a year of free credit monitoring, and thus indemnify them for any further damage resulting from the breach? Better to opt out and wait until/if you actually suffer identity theft. Even if you're forced into arbitration you'll probably get more for your individual damages.
The problem with the snarky, knee jerk response to class actions that you have is that most class actions are instances where individuals aren't harmed for much, but together it's quite significant.
And I have absolutely no faith in private arbitration to do anything but find for the entity paying their fees.
