Have I been pwned will tell me if the associated password for that site leaked. I create unique passwords per site, but lets say my mastercard login gets pwned -- that'd be one I want to change the password for right away.
I might not get an email if someone gets that account info.
In practice, anything that high-profile will be plastered all over every tech news site, twitter, reddit, probably even the news. It would be difficult for MasterCard/Visa to have dataleaks, even just email/pass, fly under the radar (I imagine...)
Oracle tried to cover up a data leak, and it didn't go great. Oracle touches nowhere near as many every-day people as MasterCard does
For ID fraud, more than an email address has to be leaked.