The substitution of bitcoin for fiat will substitute the virtue of savings/prudent spending for the vice of dis-saving/immediate indulgence. Bitcoin as currency will profoundly impact on the world's economy and culture, e.g. no more ruinous boom and bust credit cycles.
This point can't be stressed enough.
I am quite firmly convinced that the (failing) global financial/governmental system can't and will not be improved upon unless there are major changes in the underlying cultural narratives which support said systems. We can try to elect the "right people" as much as we want to but
providing systemic incentives encouraging prudent spending (spending means consuming resources!) has a much better chance at effecting positive change. This is one of my favorite things about Bitcoin and a point which the "let's regulate it and integrate it into the current system"-crowd seem to be overlooking.
A change that drastic needs time. Bitcoin will give us the opportunity to drastically change our course, if the people are smart enough to want it and do it. I am actually worried about the masses not being smart enough to understand the situation we are currently in.
Either way, if bitcoin does catch on and does not dilute into another 'bitcoin backed' system like the gold repeatedly does (by slowly but surely moving away from gold into pure fiat) it could make us more aware of our spending behavior and our economy destroying our future.
They keep saying deflation or even stagnation is bad, but i'd say inflation is worse because inflation can only sustain itself if the economy itself also inflates at the same pace, and even than it'd lead to problems for individuals. The problem with an inflationary economy is that the world will run out of resources at an exponential rate as well and we're already overproducing and exhausting the planets resources. We wouldn't even have enough resources if we had 3 planets the size of earth to mine from.