The incentives to turn bitcoin into yet another gambling platform are of fiat origin. They are very strong, but they are screwed. The potential fiat profits are great, hence the spam apologists use a lot of money and effort to achieve their goals. Being useful and unstoppable as money is the sole purpose of bitcoin. The social layer is here to protect it. Spam makes bitcoin less useful as money and less resistant to attacks. We are here to defend our life's savings, the future of our families is at stake here.
