I wouldn't say 0 utility but for sure not anywhere near it is now.
Tulips still have "utility" today but a single one does not buy you a house anymore ;)
I think a "single" bitcoin doesn't mean anything, especially compared to a physical good (it makes some sense when you are making a performance comparison to other CCs but not too much).
You can buy a house with enough bitcoins as long as you have buyers. You can say the same thing for tulips as well.
You can buy a house with enough bitcoins as long as you have buyers. You can say the same thing for tulips as well.