I'm curious what would be the negative ramifications of someone gaining access to these identifiers? AFAIK they are not considered PII or anything. Not saying t

I'm curious what would be the negative ramifications of someone gaining access to these identifiers? AFAIK they are not considered PII or anything. Not saying they should or should not be protected, but I'm having a difficult time thinking of what the attack vector would be. I guess having a list of your recurring SaaS services coupled with maybe a leaked password database or something could give potential attackers a list of the places to attempt using your password?