more computing power distributed = more secure coin
this is the right answer.
distribution yes, no raw hash power.
microguys point on incentive is also the case, most people take security measure on face value, not taking into account people thinking outside the square, an eg even though it'd be hard for an individual's comp power to attack btc, a pool could be formed, offer crazy incentives for people to join (while hiding the figures until combining all at time of attack), its concievable, not that hard and not that expensive.
I can figure plenty of ways to attack any crytpos, i like many just don't ann them here as it'd give others ideas.
