You should read the wiki link carefully,haha

Namely Suzhou numerals are invented by suzhouese merchants. Someone says it was invented by hangzhounese. Actually you hear in the drama Sherlock Holmes mentions Hangzhou. I still remember in my childhood such numerals were pictured on wine vases in Zhejiang. Now Sunzhou numerals are still widely applicable in Hong Kong and Macau’s' traditional business. Therefore it is reasonable Suzhou numerals appear in Chinatown as you point out the majority of Chinese there are from Canton Fujian.

I agree with you partially. It is obvious many Chinese factors and scenes are not really authentic in many western films. I call it Chinoiserie effect, which was once an art style and also my intervention to label how some western recognise China and Chinese.