I feel like the commodity vs currency argument is somewhat cyclical. Many finance professional would consider the USD as a commodity for analysis purposes. On the other hand, I tend to think that an ideal situation is where local physical transactions utilize whatever commonly accepted local currency (whether it be USD, bitcoins, or some other community currency) and if I can have my debit card and bank exchange in and out on the fly. When people ask me why my purchasing power always seems to be going up, I can tell them about the commodity aspect (scarcity) of bitcoin. When they ask me how I'm able to purchase whatever, wherever I want, I can give them the currency exchange aspect. That would be my utopia 
I'm not making a philosophical argument. It's a practical one. If tens of thousands of retailers are accepting bitcoins at their website, then the government is going to step in. There is plenty of history to support this. On the other hand, if tens of thousands of people are buying and holding bitcoins like they are beanie babies or gold coins, then you aren't likely to attract the attention of congress, yet you've met the goal of creating an alternate method for holding some of your wealth.
If the point of bitcoin is to make a stand against government invasion of our personal wealth, then bitcoin is on the right track. When/if retailers accept bitcoins you can bet the government will be there to regulate and tax them.