That's functional, and doesn't need additional consent. The consent for that is given by pressing the login button.
You can login and buy things. But how do you choose whether the shop can kleep track of what you have bought to suggest rebuying or for you to keep a shoopping list. Requestion those is more than login.
> track of what you have bought to suggest rebuying
You know what you sold, no need to track user behaviour.
That's functional, and doesn't need additional consent. The consent for that is given by pressing the login button.