BitCoin's fluctuating popularity has made it's value extremely unstable, making it unsuitable for use as money. Money has to be a stable unit of account as well as a predictable store of value, characteristics BitCoin doesn't have.

Basically, BitCoin for the time being is an interesting asset/investment, but not a very good cash replacement.

The best current use case is transferring money. Assuming bitcoin is relatively stable hour to hour (which I think it is) and both sender and receiver have access to an exchange that will convert bitcoins to their local currency, it can be effectively used to avoid large bank charges.

As long as the sender converts their money just prior to paying and the receiver converts back to local currency soon afterwards, there should be no problems.

I guess the big assumption here is both parties have access to a reliable exchange that can easily handle the volume of currency being transferred.

So you've just replaced traditional fees with two exchange fees.

But with each exchange fee only 0.65% (MtGox's highest rate), 1.3% is competitive with many other transfer methods.

Now add the fee to get money into the exchange and another fee to get money out.

$0.25 per transaction using dwolla. Roughly $5 to use SEPA. or worst case $15 bank transfer.

Compare that to the fees charged by Western Union or Money Bookers or credit card companies.. You're looking at $30 minimum + 6%-12%

Actually since the beginning of the year bitcoin's price has been relatively stable, around the $5 mark.

Whether this is the natural market price or if there is manipulation going on is hard to tell.

Certainly bitcoin is more volatile than the dollar, pound or euro but those currencies fluctuate in value too.

Bitcoin will be volatile whilst new coins are being minted, it is in an inflationary phase and the only upwards pressure will come from demand outstripping the supply.

I refer the honourable commenter to Jumpcrisscross' comment here: http://news.ycombinator.com/item?id=3787375, wherein they point out that to currency traders, Bitcoin's vulnerabilities have been known for a hundred years.

I can see cases where the delay before the bitcoin network approves your transaction would be problematic.

to start, you need internet accessibility for a transfer, not to get into the economics that make bitcoin unstable.

This is more like a credit card that we can use to pay one another directly, than a new monetary system.

Why not use both? Competition in this space can only be a good thing.