[boon]

The concept of a cryptocurrency subsumes traditional currency. You cannot just say, "bitcoin is not a currency". Well of course it isn't! It's an entirely different animal.

It would be like saying the Internet is not a phone system.

[tfinniga]

I think the main thing is that he's unsure what the value of bitcoin is. The value of a currency is pretty well understood at this point.

There is still a lot of uncertainty in assessing the value of bitcoin. Is it more like bullion? Currency? Tulip bulbs? The answer is like you said, it's something new, but it's not clear yet how to properly value that. If you don't fully understand where the value comes from, then it's safest to not invest.