They don't require a membership, per se. I think that having a login is intended to streamline things during this pandemic, as the store is closed. I can buy something from them online and after placing the order, I'll get an email telling me my item is ready to be picked up. Then I go to the store, call from the sidewalk, and they'll set the item outside their door for me to grab. I don't need to give them an email or a phone number with each order--it's just tied to my account and the email shows up once they've pulled my item from the shelf.
Of course you can order something and have it shipped to you, and I think there's an option to purchase something without setting up an account. But for locals, it's fairly convenient to have your information on record to facilitate pick-ups during the pandemic. (Before the lockdown began, you could go into the store and buy whatever you want without so much as giving them your name, if you were so inclined).