I am a skeptical person by nature and don't believe that someone would provide such service for free..
By entering your email address there, you are telling them that you care about it and Hence there are high chances that it contains some valuable information.
I get your point and I understand the point you're trying to drive home. The website did make one thing clear
As with any website, if you're concerned about the intent or security, don't use it.
If you're not comfortable with using IhaveBeenPwned, You can use
Mozilla Monitor . It's not every website that provides a value for FREE that is actually bad.