Tea for cleaning utensils - Hong Kong

Washing utensils such as chopsticks in hot tea is quite a usual practice in some older cafes of Hong Kong. Sometimes, we are really not sure if we should drink the tea or use it to clean/"sterilize" the utensils. After several observations of locals doing the cleaning/"sterilizing", we reckon that was the thing to do... .... .... .....or not ?

*Taken few months back in Hong Kong