The title of this question is a bit hard to word concisely, partially due to my own lack of terminology. What I am trying to ask is, when signing up for a service in a personal capacity (say Airbnb) that hosts sensitive information (like credit card details), from a cybersecurity perspective is it safer to create a new account for that service specifically (with a unique username and password of course) or to associate an already existing account provided by a larger player like Google or Apple?
On one hand it seems that creating a new, unique account for each service is safer because if your account for one service is breached, your accounts for other services are safe. Versus if you had many services associated with a single account with a large player like Google, there is a single point of failure in that if that account is compromosed - all your accounts are compromised.
On the other hand, the latter relies on the assumption that the security measure for each service are all "good enough", which given the state of many organizations likely isn't true (security is often sidelined, improperly implemented, etc.). However for many large, established entities like Google or Apple - the are likely to have some of the best security measures anywhere. So while it is a single point of failure, the likelihood of it failing is presumably much lower than any other service.
I guess I'm basically trying to ask is it better to have a single really, really, really strong account shared across many different services, or many presumably weaker & unique accounts for each service? Can anyone offer any insights as to which might be more correct?