I have been hoping to bring some convenience to a shop I'm building. My day job is security based but what I am about to ask hasn't really been exploded yet. Client side login or in other words device based login. How safe is it to use this as a sort of 2 stage profile. You can login without a password but and store your name and maybe view recent orders. However to actually edit sensitive details or make purchases you need to enter a password which will go to a server for processing.

Is this silly complex?