We should know that to increase its value our money should be out of our pocket and circulate in the economy
like in real economy
Though it is important for bitcoin economy that most of the bitcoins should be in circulation but i don't think that just because if some of us hold some of our coins the economy will be affected at all.. because we don't hold hundreds or thousands of bitcoin and nor we can because at the end of the day we will have to use them somewhere..