There's a lot of irony in this argumentation. Bitcoin certainly makes for a challenge in these discussions, because it's unlike anything else.
If you're talking to a regular Joe (not Another Joe) on the street who is likely ignorant of Austrian economics, you're right because they compare it to state issued fiat. It's the closest thing to money we have available, falling into a new no-man's land between precious metals and centralized fiat.
If you're talking to an Austrian economist, they'll point out that bitcoin does not actually fully fit the definition. It fits most of the definition. It fits better than centralized state issued fiat. But it falls slightly short in that it does not have inherent value (some use the word "intrinsic" here, but it does not fit. Only life has intrinsic value).
But, because of mining, BTC has a sort of new version of inherent value that state fiat does not. At the same time, it does not have inherent value in the same way gold does.
So, if someone thinks state issued fiat is money, they are already wrong in their thinking. It is not, from a historical perspective. But, from their standpoint, BTC would be considered money, even more so than the empty promises they already call money.
BUT, if someone has an Austrian perspective, then they also won't be able to think of BTC as fully fitting the historical definition. That doesn't take from BTC's value or importance. It's just a challenge to categorize it using historical definitions.
BTW, if email is mail, then how about emailing me some tomato seeds? ;) It highlights the same challenge.