Actually, there are several considerations.
I prefer to set up and also to buy from sites that never - ever want my information, other than what is needed to sell me what I want. No account, not now, not later. I'll give you my card info, but I don't want an "account", I don't want a username, I don't want a password. If I ever buy again, I'll enter it all again, thank you.
Unless - it's a wholesale account where I am buying on a weekly or otherwise regular basis. Then I want to login, place my order and in those cases I want my card info on file and I don't want to have to enter it each time.
So, big difference. Wholesale, no problem with logins. Retail, ask too much and I'll just go elsewhere.
This is something you have to decide on your own. There is no cut and dried solution. And you should keep this in mind when choosing a cart. Some don't even have the capability to keep up with ciustomers. Some force them to register and jump hoops no matter what. And some are in between, or have an off/on switch for register/login.
It's actually your choice.