I am not sure this is a plus. If the value of Bitcoin keeps going up, almost by-design and de-facto, then everyone holds and nobody uses Bitcoin to buy things. Then Bitcoin is only a means of speculation and not a currency, and I am not sure that is a huge success.
It is a plus because if I make a decision to invest my BTC in an entrepreneurial undertaking, I have to be convinced that I'm making a sound, profitable decision. If my business or investment won't pay off more than just holding BTC, then I hold. "Hard money" incentivizes better decision making, which is the opposite of the effect caused by easy money / credit expansion which encourages me to just throw money at projects that might not be sustainable (buying a house I can't afford, opening stupid businesses, consuming too much, etc).
Biggest problem: 51% attack by an entity wishing to destroy Bitcoin. But I am paranoid.