That seems like a type error on your part. O(unit) is a categorically different notation than O(mathematical function). You must be confusing it with the asymptotic notion that is the latter. But units are not functions and so clearly it cannot be the same notation.

No, and it’s absurdly petty to argue otherwise.

One might say it's also pretty petty to call out a casual usage of a notation being used in a way that people in the thread are understanding just fine...

I think it’s helpful because it is a common mistake.