To be fair, zero is a complicated number
For everyone who don't know, this is the complicated version of Chinese numbers. In modern days, they are mostly used in writing cheques, because these characters are not as easily modified as the simple version.
Even as a Hongkonger myself, I have no idea. We just see these characters as ancient numbers.
Also, if you write 柒 in an informal context, it is considered offensive.
For everyone who don't know, this is the complicated version of Chinese numbers. In modern days, they are mostly used in writing cheques, because these characters are not as easily modified as the simple version.
Even as a Hongkonger myself, I have no idea. We just see these characters as ancient numbers.
Also, if you write 柒 in an informal context, it is considered offensive.