Many people use the same password at difference sites – including for their email. So if your account info was among those hacked in the many online data thefts over the last few years, those passwords may be floating around.
[You can check https://haveibeenpwned.com/ to see if your email address is “out there”]
So of what possible value could your hacked email account be to the “bad guys”? Here are some ideas, from Krebs on Security:
Want more details?
https://krebsonsecurity.com/2013/06/the-value-of-a-hacked-email-account/