There is one fundamental design element that makes that bitcoin can never be a good store of value. This does not mean that bitcoin is doomed,but in my view its main purpose – if any – in the future will be on facilitating transactions,not carrying value over time. Or to put it differently: bitcoin might possibly become a good system for effectuate electronic transfers,but if too many people see it as a store of value and start hoarding then bitcoin can not survive

The design element in question is how bitcoins are mined,and what the mining reward are.As I have explained in detail in my lecture on bitcoins (and alluded to in my response to Krugman) the way that bitcoin is kept secure is by making sure that there are enough miners online at any given point in time so that (in terms of energy usage,mainly) it is too costly to control 50%+ of the mining pool which is needed to trick the system.

As I have explained in the lecture using the two charts below

the mining pool will adapt to changes in the monetary value reward by adding or removing (the marginal) resources: the more money can be earned mining bitcoins,the more miners will be online,and the more expensive will it be to control 50%+ of the pool. What I have graphed in the charts above is what happens when the monetary ($, €) value of bitcoins falls,but the same happens of course if the mining reward – in bitcoins – changes,as it does every approximately 4 years.

Source: www.oditorium.com