Because the phrase specialized math problems is not transparent. It sounds like something W.C. Fields might say with his pirate's smile. A lot of people reading it may wonder who or what centralized entity is devising the specialized problems for the miners to solve -- and even think that each new block requires new specialized -- customized -- problems. My point is not to single out the author, but to observe that the phrase might be an indicator that the Bitcoin system is a long way from popular understanding -- and popular use. But that's OK -- institutions and businesses may lead the way this time. Bitcoin use could trickle down, not up. I suspect that will be the case.