https://www.experian.com/ is the primary domain of the company.

https://www.experianidworks.com/ is a "decorated" domain for a service offered by the same company.

Anyone could register experian*.com. So, if I want to determine whether the decorated domain is actually part of Experian or not, I'd have to go to Experian's website and dig around for a link to it. What makes it even worse in this case is that Experian is an incredibly high value target.