First，you can compare the product to others by yourself at the pot;
second，you can smell、touch、observe even taste the product;
third，if you have bought the product,and find it isn't fit for you later,you can exchange it easily;
last，if you decide buy something,you don't wait for a long time and you can own it at once.
That's all，thank you!
Please accept my answer,
Thank you!