At present, a large number of credit cards are settled by signature in accordance with international practice, and there is a certain risk of misappropriation. It is stipulated that salespersons need to go through the training of signing inspection and sign inspection during the transaction, but it is rarely standardized in China at present.
So, it doesn't matter, but you can't do this when you meet a responsible cashier.
You'd better not write your full name.