It's not. The nfo databases simply show that every PC game has and will be pirated. I won't post the link, but just type nfohump into google. I'm using that example to simply point out that these aggressive protection schemes are not needed.
A simple disc check will stop most casual piracy (for retail discs) as you can't simply have your friend install and play the game. You'd need the disc in order to play the game, so your friend can give you the game after he's done, but you can't just install it and be on your way. That's going to stop most casual piracy, unless that person is savvy enough to go online and find a crack, or download a pirated version, in which case that person falls outside of "casual". I'm talking about the average computer user here, which is a category most PC users fall into. Just search google for evidence on that fact.
A disc check isn't going to stop other forms of piracy, like torrents, the asian black market, etc.. nor am I claiming it will. I'm simply saying a disc check on retail versions is enough. Having securom phoning home isn't doing anything but annoying legit customers and IMO is an unneeded waste of money for the publisher.