When you get a credit card, on the back it typically says something like - "Your card is issued and serviced by XYZ Bank pursuant to a license from Visa USA. Its use is subject to the terms of your Cardmember agreement".
The credit card isn't really your property, it is the property of the bank, and you are just being allowed to use it for payments.
When you sign up for an account online and create a username and password, that website has a decision to make:
- Those credentials belong to the website. They aren't the users property, they are the property of the website and their use, etc. is subject entirely to the terms-of-service of that website.
- Those credentials belong to the user. Their use, when the user should use them, where else the user uses them, etc. are entirely in control of the customer.
Since users often (always?) reuse credentials across websites, etc. any individual websites attitude towards user credentials is dictated a lot about how they view user credentials.
A website that would like to pretend that credential reuse doesn't occur, or isn't its concern, might not protect them in the same way as a website that believes users maintain a sort of property interest in those credentials, might use them at other sites, and only the user themselves can make a decision about exactly how important those credentials are.
I'm not suggesting that one is right or wrong, but that I think this attitude towards credentials and who owns them can play a major role in how websites view their rights and obligations as it relates to their users.